<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:ab325b64-f897-49ec-b137-7b269bb4fea4,g:05318137-9006-4915-8ed6-dd1c1eb29735-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunaudited" xlink:type="simple" xlink:href="bkh-20210930.xsd#CondensedConsolidatedStatementsofComprehensiveIncomeunaudited"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunaudited" xlink:type="extended" id="ifcf43924bc264915bb2b055f16ba8a9c_CondensedConsolidatedStatementsofComprehensiveIncomeunaudited">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_32756a4e-bed0-4ded-a272-23e6761791f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_77f87ba7-31a6-44dd-b6e0-8c3546c295c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_32756a4e-bed0-4ded-a272-23e6761791f7" xlink:to="loc_us-gaap_ProfitLoss_77f87ba7-31a6-44dd-b6e0-8c3546c295c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_32756a4e-bed0-4ded-a272-23e6761791f7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_d200d1f1-0153-4df2-bc80-dfceaff66168" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_d200d1f1-0153-4df2-bc80-dfceaff66168" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax_72c30f69-6c08-4fb5-ba2d-bb1529aaf830" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax_72c30f69-6c08-4fb5-ba2d-bb1529aaf830" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_1d34c8c4-d63d-4ecc-a8e4-99dfef2cfaf2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_1d34c8c4-d63d-4ecc-a8e4-99dfef2cfaf2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_a34df993-59af-45ad-8fa1-7799bbcc475a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_a34df993-59af-45ad-8fa1-7799bbcc475a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAdjustmentsAfterTax_3ed66ba2-006a-4d4b-a41f-d6756c2a107a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAdjustmentsAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAdjustmentsAfterTax_3ed66ba2-006a-4d4b-a41f-d6756c2a107a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_d6b19c5b-b26b-4dca-9fa8-af44cdee3cd1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_d6b19c5b-b26b-4dca-9fa8-af44cdee3cd1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_40991b66-60b9-4cea-aa8c-00bce62705d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_40991b66-60b9-4cea-aa8c-00bce62705d6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_c5876308-b51d-429f-901b-4d46755df621" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_c5876308-b51d-429f-901b-4d46755df621" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_72f6b13f-9868-47c8-840a-5cbd05bdd832" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_6cc4807d-b454-411b-b265-b2c122c9bbc9" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_72f6b13f-9868-47c8-840a-5cbd05bdd832" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_3a2d3985-5b36-43e8-b886-579368c9cfb2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_32756a4e-bed0-4ded-a272-23e6761791f7" xlink:to="loc_us-gaap_StatementTable_3a2d3985-5b36-43e8-b886-579368c9cfb2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_3be5c1d2-39ec-4842-bb1c-29d01a706d86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3a2d3985-5b36-43e8-b886-579368c9cfb2" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_3be5c1d2-39ec-4842-bb1c-29d01a706d86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_3be5c1d2-39ec-4842-bb1c-29d01a706d86_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3be5c1d2-39ec-4842-bb1c-29d01a706d86" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_3be5c1d2-39ec-4842-bb1c-29d01a706d86_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_020109a4-fcb8-44c0-93cc-ab9468f71ba3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3be5c1d2-39ec-4842-bb1c-29d01a706d86" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_020109a4-fcb8-44c0-93cc-ab9468f71ba3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_714b2e9f-32b1-4f77-80cf-eb422d98b35d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_020109a4-fcb8-44c0-93cc-ab9468f71ba3" xlink:to="loc_us-gaap_InterestRateSwapMember_714b2e9f-32b1-4f77-80cf-eb422d98b35d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_8f2b7e7a-d80b-4943-bd1b-0a13d605269d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_020109a4-fcb8-44c0-93cc-ab9468f71ba3" xlink:to="loc_us-gaap_CommodityContractMember_8f2b7e7a-d80b-4943-bd1b-0a13d605269d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical" xlink:type="simple" xlink:href="bkh-20210930.xsd#CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical" xlink:type="extended" id="ibcaf447b258c4c46bb4282db544d4931_CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_b883ddd1-bc44-4976-ae2f-2c3d55178856" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_4b1a0939-57a0-4cc9-8e4d-0edd909b2cdf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b883ddd1-bc44-4976-ae2f-2c3d55178856" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_4b1a0939-57a0-4cc9-8e4d-0edd909b2cdf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect_e1715027-eec2-4b13-af57-af45caa5a7e2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b883ddd1-bc44-4976-ae2f-2c3d55178856" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect_e1715027-eec2-4b13-af57-af45caa5a7e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax_f78c8b82-4c55-4972-9341-0a272ca0994e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b883ddd1-bc44-4976-ae2f-2c3d55178856" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax_f78c8b82-4c55-4972-9341-0a272ca0994e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax_13ad7973-1c1d-459a-82d2-4439a6d7217f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b883ddd1-bc44-4976-ae2f-2c3d55178856" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax_13ad7973-1c1d-459a-82d2-4439a6d7217f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAdjustmentsTax_5f5e0997-2e32-4717-b4d6-f146bb06b15e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAdjustmentsTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b883ddd1-bc44-4976-ae2f-2c3d55178856" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAdjustmentsTax_5f5e0997-2e32-4717-b4d6-f146bb06b15e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_8704ec16-ce58-487b-adfb-d932ee751dbe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_b883ddd1-bc44-4976-ae2f-2c3d55178856" xlink:to="loc_us-gaap_StatementTable_8704ec16-ce58-487b-adfb-d932ee751dbe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_1e4db00b-d63a-4847-99ca-d989846b4569" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_8704ec16-ce58-487b-adfb-d932ee751dbe" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_1e4db00b-d63a-4847-99ca-d989846b4569" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1e4db00b-d63a-4847-99ca-d989846b4569_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1e4db00b-d63a-4847-99ca-d989846b4569" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1e4db00b-d63a-4847-99ca-d989846b4569_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_005d15c4-68f1-435b-8c84-59eab49a56e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1e4db00b-d63a-4847-99ca-d989846b4569" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_005d15c4-68f1-435b-8c84-59eab49a56e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_4172e55c-5538-47fa-9bab-5b0fabe34337" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_005d15c4-68f1-435b-8c84-59eab49a56e6" xlink:to="loc_us-gaap_InterestRateSwapMember_4172e55c-5538-47fa-9bab-5b0fabe34337" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_5c3cec0f-4192-4144-8aea-edd690723b59" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_005d15c4-68f1-435b-8c84-59eab49a56e6" xlink:to="loc_us-gaap_CommodityContractMember_5c3cec0f-4192-4144-8aea-edd690723b59" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofEquityunaudited" xlink:type="simple" xlink:href="bkh-20210930.xsd#CondensedConsolidatedStatementsofEquityunaudited"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofEquityunaudited" xlink:type="extended" id="ib67001c881504b019f5f57d4150d1d0b_CondensedConsolidatedStatementsofEquityunaudited">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_cae1cd72-abc9-4b29-830f-52c7acf4407f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_cae1cd72-abc9-4b29-830f-52c7acf4407f" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_d72a67d7-031b-4742-a4c7-3637c8bdf75b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_d72a67d7-031b-4742-a4c7-3637c8bdf75b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_5ba15104-eb61-4e8d-99a7-761f6c4bac08" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_5ba15104-eb61-4e8d-99a7-761f6c4bac08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_1fb54ecf-378b-45ac-b111-c86808386baf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_ProfitLoss_1fb54ecf-378b-45ac-b111-c86808386baf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_906ee849-668d-4319-b289-0296fdacbb9f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_906ee849-668d-4319-b289-0296fdacbb9f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_25b42976-afb2-4e49-8603-ad7bb889f89d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_DividendsCommonStockCash_25b42976-afb2-4e49-8603-ad7bb889f89d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_8e088ff9-da29-4ae7-8442-88020d2a3cb4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_8e088ff9-da29-4ae7-8442-88020d2a3cb4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_099d0e10-d355-4abb-9bfb-a089693045c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_099d0e10-d355-4abb-9bfb-a089693045c8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_95c95f0c-8423-4298-8a56-0969dfe52d30" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_95c95f0c-8423-4298-8a56-0969dfe52d30" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_ae2ff07c-419a-409c-8de5-8e96ece5a879" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_ae2ff07c-419a-409c-8de5-8e96ece5a879" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_3eb031c9-0b40-42a2-8776-5fac9113710a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_3eb031c9-0b40-42a2-8776-5fac9113710a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_4e42dc6f-fec4-4093-95db-41f6fa8b114c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_StockholdersEquityOther_4e42dc6f-fec4-4093-95db-41f6fa8b114c" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_c3991cb4-5218-440b-bf73-65bc34379d4e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_a2e0d07a-8f5a-4e29-9330-65f124dcfd62" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_c3991cb4-5218-440b-bf73-65bc34379d4e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_54e52272-68db-4bbe-9e9c-fc0461280f8c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_f2212f58-ae60-4d23-9f07-e14ce57addf3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_e17b9ef2-c347-4087-ad9f-fc2f7f0e9899" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_cae1cd72-abc9-4b29-830f-52c7acf4407f" xlink:to="loc_us-gaap_StatementTable_e17b9ef2-c347-4087-ad9f-fc2f7f0e9899" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_5efb54fd-8c8d-4e50-a802-0d38722db43e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_e17b9ef2-c347-4087-ad9f-fc2f7f0e9899" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_5efb54fd-8c8d-4e50-a802-0d38722db43e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_5efb54fd-8c8d-4e50-a802-0d38722db43e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_5efb54fd-8c8d-4e50-a802-0d38722db43e" xlink:to="loc_us-gaap_EquityComponentDomain_5efb54fd-8c8d-4e50-a802-0d38722db43e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_5efb54fd-8c8d-4e50-a802-0d38722db43e" xlink:to="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_9a50cf9c-2e23-40b2-9c19-840627cc6af3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:to="loc_us-gaap_CommonStockMember_9a50cf9c-2e23-40b2-9c19-840627cc6af3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember_ed3772f9-bcc8-44f4-8d98-a1b03551e832" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:to="loc_us-gaap_TreasuryStockMember_ed3772f9-bcc8-44f4-8d98-a1b03551e832" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_0f479d5f-27ae-4f8d-a414-832754d0d1e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_0f479d5f-27ae-4f8d-a414-832754d0d1e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_6b2a6c5e-bb16-4225-99e8-8175e1057b55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:to="loc_us-gaap_RetainedEarningsMember_6b2a6c5e-bb16-4225-99e8-8175e1057b55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f637b530-be12-40f1-aa45-9f7614ad1346" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f637b530-be12-40f1-aa45-9f7614ad1346" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_e0d1849f-a36e-4cf1-bebf-3df12fb9ecb2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_87931477-706d-43cf-9183-6710a208973d" xlink:to="loc_us-gaap_NoncontrollingInterestMember_e0d1849f-a36e-4cf1-bebf-3df12fb9ecb2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c661fcb3-bb9f-43c3-be49-a66b416bc3fc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_e17b9ef2-c347-4087-ad9f-fc2f7f0e9899" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c661fcb3-bb9f-43c3-be49-a66b416bc3fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_c661fcb3-bb9f-43c3-be49-a66b416bc3fc_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c661fcb3-bb9f-43c3-be49-a66b416bc3fc" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_c661fcb3-bb9f-43c3-be49-a66b416bc3fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_24122697-9c41-4c6e-aec3-63c764d96a6e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c661fcb3-bb9f-43c3-be49-a66b416bc3fc" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_24122697-9c41-4c6e-aec3-63c764d96a6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_acf21d8f-b96e-4b5a-9d62-7909e4782183" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_24122697-9c41-4c6e-aec3-63c764d96a6e" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_acf21d8f-b96e-4b5a-9d62-7909e4782183" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RegulatoryMattersDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersDetails" xlink:type="extended" id="i3b5bc13e3cfb4394814952abdaab1f92_RegulatoryMattersDetails">
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c23868cf-d432-41bc-84eb-9761d4be0d51" xlink:href="bkh-20210930.xsd#bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetRegulatoryAssetsAbstract_0899807f-b096-43ba-bb92-e0e0a146d22a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetRegulatoryAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c23868cf-d432-41bc-84eb-9761d4be0d51" xlink:to="loc_us-gaap_NetRegulatoryAssetsAbstract_0899807f-b096-43ba-bb92-e0e0a146d22a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssets_4b2bb78a-25be-4940-8f8b-b99478fa246c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetRegulatoryAssetsAbstract_0899807f-b096-43ba-bb92-e0e0a146d22a" xlink:to="loc_us-gaap_RegulatoryAssets_4b2bb78a-25be-4940-8f8b-b99478fa246c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsCurrent_45e2bab5-2d3d-4d4f-aebc-ea88dd657c17" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetRegulatoryAssetsAbstract_0899807f-b096-43ba-bb92-e0e0a146d22a" xlink:to="loc_us-gaap_RegulatoryAssetsCurrent_45e2bab5-2d3d-4d4f-aebc-ea88dd657c17" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsNoncurrent_695f2367-8287-4c52-987a-4eb6bcda10d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetRegulatoryAssetsAbstract_0899807f-b096-43ba-bb92-e0e0a146d22a" xlink:to="loc_us-gaap_RegulatoryAssetsNoncurrent_695f2367-8287-4c52-987a-4eb6bcda10d6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_8b3b8908-334e-4f39-b3e6-2ad644cd9e74" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c23868cf-d432-41bc-84eb-9761d4be0d51" xlink:to="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_8b3b8908-334e-4f39-b3e6-2ad644cd9e74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilities_b51778ce-0c2f-4665-9464-b8dbff7beb7a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_8b3b8908-334e-4f39-b3e6-2ad644cd9e74" xlink:to="loc_us-gaap_RegulatoryLiabilities_b51778ce-0c2f-4665-9464-b8dbff7beb7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityCurrent_f1c999b9-e8a2-40fe-81cd-93d070eff928" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_8b3b8908-334e-4f39-b3e6-2ad644cd9e74" xlink:to="loc_us-gaap_RegulatoryLiabilityCurrent_f1c999b9-e8a2-40fe-81cd-93d070eff928" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityNoncurrent_a7fd147a-aa53-4ea9-950c-67485409a4e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_8b3b8908-334e-4f39-b3e6-2ad644cd9e74" xlink:to="loc_us-gaap_RegulatoryLiabilityNoncurrent_a7fd147a-aa53-4ea9-950c-67485409a4e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_a5513024-8f47-45c5-9bbb-59de226a26c5" xlink:href="bkh-20210930.xsd#bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c23868cf-d432-41bc-84eb-9761d4be0d51" xlink:to="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_a5513024-8f47-45c5-9bbb-59de226a26c5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAxis_83eb480b-f4cd-4271-88bd-636c3c46e674" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_a5513024-8f47-45c5-9bbb-59de226a26c5" xlink:to="loc_us-gaap_RegulatoryAssetAxis_83eb480b-f4cd-4271-88bd-636c3c46e674" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_83eb480b-f4cd-4271-88bd-636c3c46e674_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAssetAxis_83eb480b-f4cd-4271-88bd-636c3c46e674" xlink:to="loc_us-gaap_RegulatoryAssetDomain_83eb480b-f4cd-4271-88bd-636c3c46e674_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAssetAxis_83eb480b-f4cd-4271-88bd-636c3c46e674" xlink:to="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StormCostsMember_834a3912-51a8-4c22-af4d-afa5e882a952" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StormCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_us-gaap_StormCostsMember_834a3912-51a8-4c22-af4d-afa5e882a952" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFuelCostsMember_16cae10e-74ec-42ad-bc1c-00f03b42ee32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFuelCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_us-gaap_DeferredFuelCostsMember_16cae10e-74ec-42ad-bc1c-00f03b42ee32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRecoverableGasCostsMember_a6301a3b-f5a5-41d8-9913-79148b54c9cc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetRecoverableGasCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_us-gaap_AssetRecoverableGasCostsMember_a6301a3b-f5a5-41d8-9913-79148b54c9cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PriceRiskDerivativeMember_467702b1-eaad-4836-ae6a-53d88b216b6e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PriceRiskDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_us-gaap_PriceRiskDerivativeMember_467702b1-eaad-4836-ae6a-53d88b216b6e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AllowanceForFundsUsedDuringConstructionMember_ebf0fef1-1c1c-4408-8d9a-144f8b9c8922" xlink:href="bkh-20210930.xsd#bkh_AllowanceForFundsUsedDuringConstructionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_bkh_AllowanceForFundsUsedDuringConstructionMember_ebf0fef1-1c1c-4408-8d9a-144f8b9c8922" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_91a5a58c-6359-4ebf-8aba-db36438a9422" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementPlansCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_91a5a58c-6359-4ebf-8aba-db36438a9422" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_EnvironmentalMember_cb642ae7-a4fe-4053-861b-74cabe6502f8" xlink:href="bkh-20210930.xsd#bkh_EnvironmentalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_bkh_EnvironmentalMember_cb642ae7-a4fe-4053-861b-74cabe6502f8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossOnReacquiredDebtMember_28476c3f-1c13-4cb4-bcf7-e31f8d478bbe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossOnReacquiredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_us-gaap_LossOnReacquiredDebtMember_28476c3f-1c13-4cb4-bcf7-e31f8d478bbe" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FlowThroughAccountingMember_80728fb6-42e9-4015-83b4-3dfc399b89e1" xlink:href="bkh-20210930.xsd#bkh_FlowThroughAccountingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_bkh_FlowThroughAccountingMember_80728fb6-42e9-4015-83b4-3dfc399b89e1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRestorationCostsMember_6dcdf9a4-ea7a-4b32-9996-1f5035d82fbc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EnvironmentalRestorationCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_us-gaap_EnvironmentalRestorationCostsMember_6dcdf9a4-ea7a-4b32-9996-1f5035d82fbc" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasSupplyContractTerminationMember_08dd3fee-0686-4089-90e5-e4fd84a8faf6" xlink:href="bkh-20210930.xsd#bkh_GasSupplyContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_bkh_GasSupplyContractTerminationMember_08dd3fee-0686-4089-90e5-e4fd84a8faf6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherRegulatoryAssetsMember_3fb8a1ae-a3d0-43f5-80c4-33c4e573e3f1" xlink:href="bkh-20210930.xsd#bkh_OtherRegulatoryAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_efd9ef0a-db99-4ee9-b6a0-5a4f43b99e91" xlink:to="loc_bkh_OtherRegulatoryAssetsMember_3fb8a1ae-a3d0-43f5-80c4-33c4e573e3f1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityAxis_a5748c54-ec1e-4e86-8bf2-e869948b0d3a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_a5513024-8f47-45c5-9bbb-59de226a26c5" xlink:to="loc_us-gaap_RegulatoryLiabilityAxis_a5748c54-ec1e-4e86-8bf2-e869948b0d3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_a5748c54-ec1e-4e86-8bf2-e869948b0d3a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_a5748c54-ec1e-4e86-8bf2-e869948b0d3a" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_a5748c54-ec1e-4e86-8bf2-e869948b0d3a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_a5748c54-ec1e-4e86-8bf2-e869948b0d3a" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFuelCostsMember_aa6ea073-c44e-4ea7-a56e-546a420e958a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFuelCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:to="loc_us-gaap_DeferredFuelCostsMember_aa6ea073-c44e-4ea7-a56e-546a420e958a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PriceRiskDerivativeMember_2a121ae1-e276-4468-81fc-3fb771860573" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PriceRiskDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:to="loc_us-gaap_PriceRiskDerivativeMember_2a121ae1-e276-4468-81fc-3fb771860573" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_4d5e124b-f65b-4b03-93ff-f2e47cfe537d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementPlansCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:to="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_4d5e124b-f65b-4b03-93ff-f2e47cfe537d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RemovalCostsMember_516a1334-ecde-483d-8356-bfc9bdc65fee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RemovalCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:to="loc_us-gaap_RemovalCostsMember_516a1334-ecde-483d-8356-bfc9bdc65fee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DeferredIncomeTaxChargesaMember_bd76fb8f-53ee-4d5d-b082-044cd2898110" xlink:href="bkh-20210930.xsd#bkh_DeferredIncomeTaxChargesaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:to="loc_bkh_DeferredIncomeTaxChargesaMember_bd76fb8f-53ee-4d5d-b082-044cd2898110" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherRegulatoryLiabilitiesMember_9a56631f-e37b-45a0-a832-c6d6fde357aa" xlink:href="bkh-20210930.xsd#bkh_OtherRegulatoryLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_ac3aaaec-e796-449b-900d-a9c16f9fbb96" xlink:to="loc_bkh_OtherRegulatoryLiabilitiesMember_9a56631f-e37b-45a0-a832-c6d6fde357aa" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersWinterStormUriDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RegulatoryMattersWinterStormUriDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersWinterStormUriDetails" xlink:type="extended" id="id231d92843674c13b546ba93729e7e11_RegulatoryMattersWinterStormUriDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_3e520919-f43d-4eef-b75b-40a05d86f70c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssets_90836319-5d7d-4bcc-88ae-330f73d2f78e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_3e520919-f43d-4eef-b75b-40a05d86f70c" xlink:to="loc_us-gaap_RegulatoryAssets_90836319-5d7d-4bcc-88ae-330f73d2f78e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAmortizationPeriod_d3fbffdb-5504-4ea4-95c7-d916da2521e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetAmortizationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_3e520919-f43d-4eef-b75b-40a05d86f70c" xlink:to="loc_us-gaap_RegulatoryAssetAmortizationPeriod_d3fbffdb-5504-4ea4-95c7-d916da2521e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AmountRecoveredThroughRegulatoryMechanism_e2f50aec-01fa-4f1a-92e9-f3197f554fc2" xlink:href="bkh-20210930.xsd#bkh_AmountRecoveredThroughRegulatoryMechanism"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_3e520919-f43d-4eef-b75b-40a05d86f70c" xlink:to="loc_bkh_AmountRecoveredThroughRegulatoryMechanism_e2f50aec-01fa-4f1a-92e9-f3197f554fc2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a7532f64-2926-44e0-8efa-abbf38015daf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_3e520919-f43d-4eef-b75b-40a05d86f70c" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a7532f64-2926-44e0-8efa-abbf38015daf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemAxis_0a331423-e839-47aa-8613-f9261bae87c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a7532f64-2926-44e0-8efa-abbf38015daf" xlink:to="loc_us-gaap_UnusualOrInfrequentItemAxis_0a331423-e839-47aa-8613-f9261bae87c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_0a331423-e839-47aa-8613-f9261bae87c3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_0a331423-e839-47aa-8613-f9261bae87c3" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_0a331423-e839-47aa-8613-f9261bae87c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_73925ef3-b931-4d57-a5a9-820e5c7e32a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_0a331423-e839-47aa-8613-f9261bae87c3" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_73925ef3-b931-4d57-a5a9-820e5c7e32a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WinterStormUriMember_85e2fec9-dc50-4208-a3cc-c49d02bb6d26" xlink:href="bkh-20210930.xsd#bkh_WinterStormUriMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_73925ef3-b931-4d57-a5a9-820e5c7e32a1" xlink:to="loc_bkh_WinterStormUriMember_85e2fec9-dc50-4208-a3cc-c49d02bb6d26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAxis_c4a62089-2d67-49bd-90c9-4f54d0589a61" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_a7532f64-2926-44e0-8efa-abbf38015daf" xlink:to="loc_us-gaap_RegulatoryAssetAxis_c4a62089-2d67-49bd-90c9-4f54d0589a61" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_c4a62089-2d67-49bd-90c9-4f54d0589a61_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAssetAxis_c4a62089-2d67-49bd-90c9-4f54d0589a61" xlink:to="loc_us-gaap_RegulatoryAssetDomain_c4a62089-2d67-49bd-90c9-4f54d0589a61_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_839e51cf-45d7-4e43-ad45-771d6f20d4f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAssetAxis_c4a62089-2d67-49bd-90c9-4f54d0589a61" xlink:to="loc_us-gaap_RegulatoryAssetDomain_839e51cf-45d7-4e43-ad45-771d6f20d4f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StormCostsMember_2867c12c-6ad3-46e0-ae08-6180c6e18556" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StormCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_839e51cf-45d7-4e43-ad45-771d6f20d4f2" xlink:to="loc_us-gaap_StormCostsMember_2867c12c-6ad3-46e0-ae08-6180c6e18556" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_CarryingCostsMember_0558c237-00a9-445d-892a-b768c2e04f15" xlink:href="bkh-20210930.xsd#bkh_CarryingCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_839e51cf-45d7-4e43-ad45-771d6f20d4f2" xlink:to="loc_bkh_CarryingCostsMember_0558c237-00a9-445d-892a-b768c2e04f15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRecoverableGasCostsMember_96cbc626-d4ef-4443-b4d4-cf943d6ab4c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetRecoverableGasCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_839e51cf-45d7-4e43-ad45-771d6f20d4f2" xlink:to="loc_us-gaap_AssetRecoverableGasCostsMember_96cbc626-d4ef-4443-b4d4-cf943d6ab4c7" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersTaxCutandJobsActDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RegulatoryMattersTaxCutandJobsActDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersTaxCutandJobsActDetails" xlink:type="extended" id="id33c366c751546388ed99f6deb7f6732_RegulatoryMattersTaxCutandJobsActDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_87953b60-5ee4-4e9b-b479-52211e2e85e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SettlementOfPlanToProvideTCJARelatedCustomerBillingCreditsToItsCustomers_0ff82966-7427-4daa-8aa0-f0a19cae1e63" xlink:href="bkh-20210930.xsd#bkh_SettlementOfPlanToProvideTCJARelatedCustomerBillingCreditsToItsCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_87953b60-5ee4-4e9b-b479-52211e2e85e1" xlink:to="loc_bkh_SettlementOfPlanToProvideTCJARelatedCustomerBillingCreditsToItsCustomers_0ff82966-7427-4daa-8aa0-f0a19cae1e63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AnnualTCJARelatedCustomerBillingCredits_b31e147c-1d23-4261-8a48-485b07e7dfa1" xlink:href="bkh-20210930.xsd#bkh_AnnualTCJARelatedCustomerBillingCredits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_87953b60-5ee4-4e9b-b479-52211e2e85e1" xlink:to="loc_bkh_AnnualTCJARelatedCustomerBillingCredits_b31e147c-1d23-4261-8a48-485b07e7dfa1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SettlementOfPlanToProvideTCJAAndStateTaxReformBenefitsToCustomersAnnually_3ced9bf3-6064-4025-9f63-31b9f1cec8fb" xlink:href="bkh-20210930.xsd#bkh_SettlementOfPlanToProvideTCJAAndStateTaxReformBenefitsToCustomersAnnually"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_87953b60-5ee4-4e9b-b479-52211e2e85e1" xlink:to="loc_bkh_SettlementOfPlanToProvideTCJAAndStateTaxReformBenefitsToCustomersAnnually_3ced9bf3-6064-4025-9f63-31b9f1cec8fb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NumberOfYearsTCJAAndStateTaxReformBenefitsToBeProvideToCustomers_e0816aee-eb8c-4831-b30f-ccb0d309af5d" xlink:href="bkh-20210930.xsd#bkh_NumberOfYearsTCJAAndStateTaxReformBenefitsToBeProvideToCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_87953b60-5ee4-4e9b-b479-52211e2e85e1" xlink:to="loc_bkh_NumberOfYearsTCJAAndStateTaxReformBenefitsToBeProvideToCustomers_e0816aee-eb8c-4831-b30f-ccb0d309af5d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SettlementTotalOfPlanToProvideTCJAAndStateTaxReformBenefitsToCustomers_9db6fd9c-f88f-401e-9fcc-720edc2ca27d" xlink:href="bkh-20210930.xsd#bkh_SettlementTotalOfPlanToProvideTCJAAndStateTaxReformBenefitsToCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_87953b60-5ee4-4e9b-b479-52211e2e85e1" xlink:to="loc_bkh_SettlementTotalOfPlanToProvideTCJAAndStateTaxReformBenefitsToCustomers_9db6fd9c-f88f-401e-9fcc-720edc2ca27d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_4d1c8614-7ed1-4728-b2e4-26d967b63ca7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_87953b60-5ee4-4e9b-b479-52211e2e85e1" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_4d1c8614-7ed1-4728-b2e4-26d967b63ca7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyAxis_64e4c363-f202-49d5-95e4-0f51c7eafd9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_4d1c8614-7ed1-4728-b2e4-26d967b63ca7" xlink:to="loc_us-gaap_RegulatoryAgencyAxis_64e4c363-f202-49d5-95e4-0f51c7eafd9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_64e4c363-f202-49d5-95e4-0f51c7eafd9c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_64e4c363-f202-49d5-95e4-0f51c7eafd9c" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_64e4c363-f202-49d5-95e4-0f51c7eafd9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_6eb85c18-40d2-4f34-9108-cbab56cf8d4c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_64e4c363-f202-49d5-95e4-0f51c7eafd9c" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_6eb85c18-40d2-4f34-9108-cbab56cf8d4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ColoradoPublicUtilitiesCommissionCPUCMember_d7d78823-ea91-4c74-a159-069d09ec0c63" xlink:href="bkh-20210930.xsd#bkh_ColoradoPublicUtilitiesCommissionCPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_6eb85c18-40d2-4f34-9108-cbab56cf8d4c" xlink:to="loc_bkh_ColoradoPublicUtilitiesCommissionCPUCMember_d7d78823-ea91-4c74-a159-069d09ec0c63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NebraskaPublicServiceCommissionNPSCMember_e4270eca-dbc4-4d86-86b4-a9af7a12d242" xlink:href="bkh-20210930.xsd#bkh_NebraskaPublicServiceCommissionNPSCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_6eb85c18-40d2-4f34-9108-cbab56cf8d4c" xlink:to="loc_bkh_NebraskaPublicServiceCommissionNPSCMember_e4270eca-dbc4-4d86-86b4-a9af7a12d242" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_KansasCorporationCommissionKCCMember_73aacaf2-f9ec-48c4-aa01-f46ebddef3f2" xlink:href="bkh-20210930.xsd#bkh_KansasCorporationCommissionKCCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_6eb85c18-40d2-4f34-9108-cbab56cf8d4c" xlink:to="loc_bkh_KansasCorporationCommissionKCCMember_73aacaf2-f9ec-48c4-aa01-f46ebddef3f2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_402c218a-e5c3-4f52-bb60-1fecb44d991d" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_4d1c8614-7ed1-4728-b2e4-26d967b63ca7" xlink:to="loc_dei_LegalEntityAxis_402c218a-e5c3-4f52-bb60-1fecb44d991d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_402c218a-e5c3-4f52-bb60-1fecb44d991d_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_402c218a-e5c3-4f52-bb60-1fecb44d991d" xlink:to="loc_dei_EntityDomain_402c218a-e5c3-4f52-bb60-1fecb44d991d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_80160ae7-2021-4a29-ba65-c8f62542d56b" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_402c218a-e5c3-4f52-bb60-1fecb44d991d" xlink:to="loc_dei_EntityDomain_80160ae7-2021-4a29-ba65-c8f62542d56b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyColoradoElectricMember_d3ccd813-a830-4488-8d76-65dbf5fbf883" xlink:href="bkh-20210930.xsd#bkh_BlackHillsEnergyColoradoElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_80160ae7-2021-4a29-ba65-c8f62542d56b" xlink:to="loc_bkh_BlackHillsEnergyColoradoElectricMember_d3ccd813-a830-4488-8d76-65dbf5fbf883" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyNebraskaGasMember_ab68c779-459b-4307-8903-7636d9716c98" xlink:href="bkh-20210930.xsd#bkh_BlackHillsEnergyNebraskaGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_80160ae7-2021-4a29-ba65-c8f62542d56b" xlink:to="loc_bkh_BlackHillsEnergyNebraskaGasMember_ab68c779-459b-4307-8903-7636d9716c98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyKansasGasMember_d7d86103-3217-4ea3-b0ac-cf6a0bd3721c" xlink:href="bkh-20210930.xsd#bkh_BlackHillsEnergyKansasGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_80160ae7-2021-4a29-ba65-c8f62542d56b" xlink:to="loc_bkh_BlackHillsEnergyKansasGasMember_d7d86103-3217-4ea3-b0ac-cf6a0bd3721c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_1e1977c9-743c-4c80-9e85-82330f66e8c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_4d1c8614-7ed1-4728-b2e4-26d967b63ca7" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_1e1977c9-743c-4c80-9e85-82330f66e8c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_1e1977c9-743c-4c80-9e85-82330f66e8c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_1e1977c9-743c-4c80-9e85-82330f66e8c7" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_1e1977c9-743c-4c80-9e85-82330f66e8c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_53a08584-3c2c-4a25-82db-bdec266ca91e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_1e1977c9-743c-4c80-9e85-82330f66e8c7" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_53a08584-3c2c-4a25-82db-bdec266ca91e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_b173f57f-ed5e-4805-aec1-56def8072350" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_53a08584-3c2c-4a25-82db-bdec266ca91e" xlink:to="loc_us-gaap_SubsequentEventMember_b173f57f-ed5e-4805-aec1-56def8072350" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersRateReviewDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RegulatoryMattersRateReviewDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersRateReviewDetails" xlink:type="extended" id="id5ca3463c2014b3c86683035df8de2d0_RegulatoryMattersRateReviewDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesLengthOfNaturalGasPipelineToReceiveInfrastructureInvestments_d11a5b0e-a35b-4130-ad08-16b940ec65b2" xlink:href="bkh-20210930.xsd#bkh_PublicUtilitiesLengthOfNaturalGasPipelineToReceiveInfrastructureInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_bkh_PublicUtilitiesLengthOfNaturalGasPipelineToReceiveInfrastructureInvestments_d11a5b0e-a35b-4130-ad08-16b940ec65b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount_bd8addb9-4a2d-4dfb-bb5f-88b1f39f3690" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount_bd8addb9-4a2d-4dfb-bb5f-88b1f39f3690" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage_dd2f7337-f55e-48f0-ad0a-8153bbd4bcc0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage_dd2f7337-f55e-48f0-ad0a-8153bbd4bcc0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage_1fc3cff2-541e-464c-9ad5-1982c5ffc943" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage_1fc3cff2-541e-464c-9ad5-1982c5ffc943" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage_2e28b98d-9dd1-4b09-9308-c51f9c4e07d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage_2e28b98d-9dd1-4b09-9308-c51f9c4e07d6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesRequestedTermExtensionOfSystemSafetyAndIntegrityRider_74f183b2-9ac3-4865-ae88-e288c8c4da8a" xlink:href="bkh-20210930.xsd#bkh_PublicUtilitiesRequestedTermExtensionOfSystemSafetyAndIntegrityRider"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_bkh_PublicUtilitiesRequestedTermExtensionOfSystemSafetyAndIntegrityRider_74f183b2-9ac3-4865-ae88-e288c8c4da8a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesTermExtensionOfSystemSafetyAndIntegrityRider_1882fa37-e265-4860-8acd-2c6a6f568924" xlink:href="bkh-20210930.xsd#bkh_PublicUtilitiesTermExtensionOfSystemSafetyAndIntegrityRider"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_bkh_PublicUtilitiesTermExtensionOfSystemSafetyAndIntegrityRider_1882fa37-e265-4860-8acd-2c6a6f568924" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage_29a27bd4-9251-48a7-8802-b72f1e6f54ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage_29a27bd4-9251-48a7-8802-b72f1e6f54ae" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedDebtCapitalStructurePercentage_8e6da965-f00d-4a1c-b6b1-a620efcf3b1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedDebtCapitalStructurePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesRequestedDebtCapitalStructurePercentage_8e6da965-f00d-4a1c-b6b1-a620efcf3b1f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage_151d5ee0-81d1-458e-ac0e-7ce337189521" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage_151d5ee0-81d1-458e-ac0e-7ce337189521" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesAmountOfSystemSafetyAndIntegrityRiderMovedToBaseRatesRequested_cd71d881-c066-4306-a94e-35d0ad86e8a7" xlink:href="bkh-20210930.xsd#bkh_PublicUtilitiesAmountOfSystemSafetyAndIntegrityRiderMovedToBaseRatesRequested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_bkh_PublicUtilitiesAmountOfSystemSafetyAndIntegrityRiderMovedToBaseRatesRequested_cd71d881-c066-4306-a94e-35d0ad86e8a7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesNumberOfDaysAfterFilingARateReviewTheInterimRatesMayBeImplemented_43aa3455-ccdb-4eda-bdd6-0ea4c3a77afb" xlink:href="bkh-20210930.xsd#bkh_PublicUtilitiesNumberOfDaysAfterFilingARateReviewTheInterimRatesMayBeImplemented"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_bkh_PublicUtilitiesNumberOfDaysAfterFilingARateReviewTheInterimRatesMayBeImplemented_43aa3455-ccdb-4eda-bdd6-0ea4c3a77afb" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount_07ff4a48-0492-4b88-9b43-626160576aaf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount_07ff4a48-0492-4b88-9b43-626160576aaf" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_64f37b4d-44ac-47b3-9402-01b09c26724d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_813ceec9-b99f-453b-a95c-b52f098f2e9e" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_64f37b4d-44ac-47b3-9402-01b09c26724d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_2cb041ac-4d21-4c4c-9a90-dc3ebf3bcd20" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_64f37b4d-44ac-47b3-9402-01b09c26724d" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_2cb041ac-4d21-4c4c-9a90-dc3ebf3bcd20" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_2cb041ac-4d21-4c4c-9a90-dc3ebf3bcd20_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_2cb041ac-4d21-4c4c-9a90-dc3ebf3bcd20" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_2cb041ac-4d21-4c4c-9a90-dc3ebf3bcd20_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_bf3d6441-610f-4257-bb74-0183f8b563f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_2cb041ac-4d21-4c4c-9a90-dc3ebf3bcd20" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_bf3d6441-610f-4257-bb74-0183f8b563f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SettlementAgreementReachedWithCPUCStaffAndVariousIntervenorsSubjectToTheReviewAndApprovalByAnAdministrativeLawJudgeAndTheCPUCMember_4245427d-095c-4a8b-a36f-801a43aad956" xlink:href="bkh-20210930.xsd#bkh_SettlementAgreementReachedWithCPUCStaffAndVariousIntervenorsSubjectToTheReviewAndApprovalByAnAdministrativeLawJudgeAndTheCPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_bf3d6441-610f-4257-bb74-0183f8b563f4" xlink:to="loc_bkh_SettlementAgreementReachedWithCPUCStaffAndVariousIntervenorsSubjectToTheReviewAndApprovalByAnAdministrativeLawJudgeAndTheCPUCMember_4245427d-095c-4a8b-a36f-801a43aad956" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_RateReviewFiledwiththeRegulatoryAgencyMember_c9679487-f661-408f-8f77-ce54c2d4f50a" xlink:href="bkh-20210930.xsd#bkh_RateReviewFiledwiththeRegulatoryAgencyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_bf3d6441-610f-4257-bb74-0183f8b563f4" xlink:to="loc_bkh_RateReviewFiledwiththeRegulatoryAgencyMember_c9679487-f661-408f-8f77-ce54c2d4f50a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_RateReviewApprovedByRegulatoryAgencyMember_c7ed298e-f687-437e-bd9c-bcf899bf4f12" xlink:href="bkh-20210930.xsd#bkh_RateReviewApprovedByRegulatoryAgencyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_bf3d6441-610f-4257-bb74-0183f8b563f4" xlink:to="loc_bkh_RateReviewApprovedByRegulatoryAgencyMember_c7ed298e-f687-437e-bd9c-bcf899bf4f12" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GlobalSettlementAgreementWithKCCStaffAndVariousIntervenorsForAGeneralRateIncreaseAndRenewalOfItsSafetyAndIntegrityRiderMember_aaf8abac-de97-4446-a4f7-aa776b414f8a" xlink:href="bkh-20210930.xsd#bkh_GlobalSettlementAgreementWithKCCStaffAndVariousIntervenorsForAGeneralRateIncreaseAndRenewalOfItsSafetyAndIntegrityRiderMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_bf3d6441-610f-4257-bb74-0183f8b563f4" xlink:to="loc_bkh_GlobalSettlementAgreementWithKCCStaffAndVariousIntervenorsForAGeneralRateIncreaseAndRenewalOfItsSafetyAndIntegrityRiderMember_aaf8abac-de97-4446-a4f7-aa776b414f8a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ApprovalReceivedFromRegulatoryAgencyMember_f8f5556e-85e4-44a3-a24e-3e23d304da54" xlink:href="bkh-20210930.xsd#bkh_ApprovalReceivedFromRegulatoryAgencyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_bf3d6441-610f-4257-bb74-0183f8b563f4" xlink:to="loc_bkh_ApprovalReceivedFromRegulatoryAgencyMember_f8f5556e-85e4-44a3-a24e-3e23d304da54" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyAxis_ddc6d29f-837d-49e1-8dd2-f9885443c866" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_64f37b4d-44ac-47b3-9402-01b09c26724d" xlink:to="loc_us-gaap_RegulatoryAgencyAxis_ddc6d29f-837d-49e1-8dd2-f9885443c866" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_ddc6d29f-837d-49e1-8dd2-f9885443c866_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_ddc6d29f-837d-49e1-8dd2-f9885443c866" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_ddc6d29f-837d-49e1-8dd2-f9885443c866_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_92f1c0f7-b16b-43eb-97d8-763bbf815099" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_ddc6d29f-837d-49e1-8dd2-f9885443c866" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_92f1c0f7-b16b-43eb-97d8-763bbf815099" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ColoradoPublicUtilitiesCommissionCPUCMember_83f29af9-89ed-4132-adc6-fafde6c0523c" xlink:href="bkh-20210930.xsd#bkh_ColoradoPublicUtilitiesCommissionCPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_92f1c0f7-b16b-43eb-97d8-763bbf815099" xlink:to="loc_bkh_ColoradoPublicUtilitiesCommissionCPUCMember_83f29af9-89ed-4132-adc6-fafde6c0523c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_IowaUtilitiesBoardIUBMember_9c4c997b-2212-4ebf-ba04-00ebe94b4b8f" xlink:href="bkh-20210930.xsd#bkh_IowaUtilitiesBoardIUBMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_92f1c0f7-b16b-43eb-97d8-763bbf815099" xlink:to="loc_bkh_IowaUtilitiesBoardIUBMember_9c4c997b-2212-4ebf-ba04-00ebe94b4b8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_KansasCorporationCommissionKCCMember_e98863dc-9f73-49d7-9704-11eb399f2dee" xlink:href="bkh-20210930.xsd#bkh_KansasCorporationCommissionKCCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_92f1c0f7-b16b-43eb-97d8-763bbf815099" xlink:to="loc_bkh_KansasCorporationCommissionKCCMember_e98863dc-9f73-49d7-9704-11eb399f2dee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NebraskaPublcServiceCommissionNPSCMember_8949508d-b10e-4dde-918f-62c74eee3a5e" xlink:href="bkh-20210930.xsd#bkh_NebraskaPublcServiceCommissionNPSCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_92f1c0f7-b16b-43eb-97d8-763bbf815099" xlink:to="loc_bkh_NebraskaPublcServiceCommissionNPSCMember_8949508d-b10e-4dde-918f-62c74eee3a5e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_b6a389b2-68d2-4d3d-a362-e355492971a2" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_64f37b4d-44ac-47b3-9402-01b09c26724d" xlink:to="loc_dei_LegalEntityAxis_b6a389b2-68d2-4d3d-a362-e355492971a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_b6a389b2-68d2-4d3d-a362-e355492971a2_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_b6a389b2-68d2-4d3d-a362-e355492971a2" xlink:to="loc_dei_EntityDomain_b6a389b2-68d2-4d3d-a362-e355492971a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_036d8e0e-bc0d-49ac-8a6e-d4baf69d4599" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_b6a389b2-68d2-4d3d-a362-e355492971a2" xlink:to="loc_dei_EntityDomain_036d8e0e-bc0d-49ac-8a6e-d4baf69d4599" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyColoradoGasMember_89bb5dd7-1a2f-46e1-a95c-a0ecd411bba5" xlink:href="bkh-20210930.xsd#bkh_BlackHillsEnergyColoradoGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_036d8e0e-bc0d-49ac-8a6e-d4baf69d4599" xlink:to="loc_bkh_BlackHillsEnergyColoradoGasMember_89bb5dd7-1a2f-46e1-a95c-a0ecd411bba5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyIowaGasMember_00ff3063-8e59-4a9b-8004-78b44cd8b440" xlink:href="bkh-20210930.xsd#bkh_BlackHillsEnergyIowaGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_036d8e0e-bc0d-49ac-8a6e-d4baf69d4599" xlink:to="loc_bkh_BlackHillsEnergyIowaGasMember_00ff3063-8e59-4a9b-8004-78b44cd8b440" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyKansasGasMember_2295a0cd-2918-4728-ad16-bc7edbcc0413" xlink:href="bkh-20210930.xsd#bkh_BlackHillsEnergyKansasGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_036d8e0e-bc0d-49ac-8a6e-d4baf69d4599" xlink:to="loc_bkh_BlackHillsEnergyKansasGasMember_2295a0cd-2918-4728-ad16-bc7edbcc0413" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyNebraskaGasMember_b653ca38-9324-4453-95c8-461995c3459b" xlink:href="bkh-20210930.xsd#bkh_BlackHillsEnergyNebraskaGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_036d8e0e-bc0d-49ac-8a6e-d4baf69d4599" xlink:to="loc_bkh_BlackHillsEnergyNebraskaGasMember_b653ca38-9324-4453-95c8-461995c3459b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_b51f81cf-2e12-4961-92ec-8d0f7a73146f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_64f37b4d-44ac-47b3-9402-01b09c26724d" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_b51f81cf-2e12-4961-92ec-8d0f7a73146f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_b51f81cf-2e12-4961-92ec-8d0f7a73146f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_b51f81cf-2e12-4961-92ec-8d0f7a73146f" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_b51f81cf-2e12-4961-92ec-8d0f7a73146f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_3f807830-2c0f-4a39-8003-7cb4432ed5c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_b51f81cf-2e12-4961-92ec-8d0f7a73146f" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_3f807830-2c0f-4a39-8003-7cb4432ed5c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_2443facc-28f2-47d6-9614-8fc0c37b30ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_3f807830-2c0f-4a39-8003-7cb4432ed5c8" xlink:to="loc_us-gaap_SubsequentEventMember_2443facc-28f2-47d6-9614-8fc0c37b30ed" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CommitmentsContingenciesandGuaranteesDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#CommitmentsContingenciesandGuaranteesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CommitmentsContingenciesandGuaranteesDetails" xlink:type="extended" id="i837fafda30754a9bb1e9fbddb970356e_CommitmentsContingenciesandGuaranteesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_e3fcda8c-c534-4a5c-966d-ebdd3e1d0aaf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NumberOfMegawattsCapacityPurchased_68767f95-dc9e-4fca-9c12-239a416f9f4b" xlink:href="bkh-20210930.xsd#bkh_NumberOfMegawattsCapacityPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_e3fcda8c-c534-4a5c-966d-ebdd3e1d0aaf" xlink:to="loc_bkh_NumberOfMegawattsCapacityPurchased_68767f95-dc9e-4fca-9c12-239a416f9f4b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PurchasePowerAgreementSetToExpireAfterACertainNumberOfYearsFollowingCompletionOfTheFacility_d6f49575-242b-4ba8-88c3-1eebaa0e3907" xlink:href="bkh-20210930.xsd#bkh_PurchasePowerAgreementSetToExpireAfterACertainNumberOfYearsFollowingCompletionOfTheFacility"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_e3fcda8c-c534-4a5c-966d-ebdd3e1d0aaf" xlink:to="loc_bkh_PurchasePowerAgreementSetToExpireAfterACertainNumberOfYearsFollowingCompletionOfTheFacility_d6f49575-242b-4ba8-88c3-1eebaa0e3907" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a7a0af0d-b043-4780-838f-b2b7fbfa7f2c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_e3fcda8c-c534-4a5c-966d-ebdd3e1d0aaf" xlink:to="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a7a0af0d-b043-4780-838f-b2b7fbfa7f2c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_a8e788d7-15a1-4efe-ab17-e3539c9bbb3e" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a7a0af0d-b043-4780-838f-b2b7fbfa7f2c" xlink:to="loc_dei_LegalEntityAxis_a8e788d7-15a1-4efe-ab17-e3539c9bbb3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_a8e788d7-15a1-4efe-ab17-e3539c9bbb3e_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_a8e788d7-15a1-4efe-ab17-e3539c9bbb3e" xlink:to="loc_dei_EntityDomain_a8e788d7-15a1-4efe-ab17-e3539c9bbb3e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_8f95d637-dcfc-416b-97a1-e59a271dd562" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_a8e788d7-15a1-4efe-ab17-e3539c9bbb3e" xlink:to="loc_dei_EntityDomain_8f95d637-dcfc-416b-97a1-e59a271dd562" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ColoradoElectricMember_69dd3bf2-0893-494d-9b6a-cd8af78ea7a6" xlink:href="bkh-20210930.xsd#bkh_ColoradoElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_8f95d637-dcfc-416b-97a1-e59a271dd562" xlink:to="loc_bkh_ColoradoElectricMember_69dd3bf2-0893-494d-9b6a-cd8af78ea7a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b0d1b5c6-836a-47d9-aeb6-14f63440fdd2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a7a0af0d-b043-4780-838f-b2b7fbfa7f2c" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b0d1b5c6-836a-47d9-aeb6-14f63440fdd2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_b0d1b5c6-836a-47d9-aeb6-14f63440fdd2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b0d1b5c6-836a-47d9-aeb6-14f63440fdd2" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_b0d1b5c6-836a-47d9-aeb6-14f63440fdd2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_d29f17f7-6650-4e8c-9f0c-6afd51bbeecd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_b0d1b5c6-836a-47d9-aeb6-14f63440fdd2" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_d29f17f7-6650-4e8c-9f0c-6afd51bbeecd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_TCColoradoSolarLLCMember_959dc015-c3c1-465e-9d1d-3e1a010bb562" xlink:href="bkh-20210930.xsd#bkh_TCColoradoSolarLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_d29f17f7-6650-4e8c-9f0c-6afd51bbeecd" xlink:to="loc_bkh_TCColoradoSolarLLCMember_959dc015-c3c1-465e-9d1d-3e1a010bb562" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelTypeAxis_a7659f32-fcf5-446d-a404-4213d5cccd70" xlink:href="bkh-20210930.xsd#bkh_FuelTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_a7a0af0d-b043-4780-838f-b2b7fbfa7f2c" xlink:to="loc_bkh_FuelTypeAxis_a7659f32-fcf5-446d-a404-4213d5cccd70" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelTypeDomain_a7659f32-fcf5-446d-a404-4213d5cccd70_default" xlink:href="bkh-20210930.xsd#bkh_FuelTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_bkh_FuelTypeAxis_a7659f32-fcf5-446d-a404-4213d5cccd70" xlink:to="loc_bkh_FuelTypeDomain_a7659f32-fcf5-446d-a404-4213d5cccd70_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelTypeDomain_90d60586-2e35-4b90-b64a-4844e265fa38" xlink:href="bkh-20210930.xsd#bkh_FuelTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_bkh_FuelTypeAxis_a7659f32-fcf5-446d-a404-4213d5cccd70" xlink:to="loc_bkh_FuelTypeDomain_90d60586-2e35-4b90-b64a-4844e265fa38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SolarMember_211a3f51-06cc-4d8c-ac45-4391daf8b05a" xlink:href="bkh-20210930.xsd#bkh_SolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_FuelTypeDomain_90d60586-2e35-4b90-b64a-4844e265fa38" xlink:to="loc_bkh_SolarMember_211a3f51-06cc-4d8c-ac45-4391daf8b05a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RevenueDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RevenueDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RevenueDisaggregationofRevenueDetails" xlink:type="extended" id="iaf75282eaddf4aca98f06db3f7883535_RevenueDisaggregationofRevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_f3c562d5-1103-470a-80a3-5fd11bd57c9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_ca1ba3bf-4f00-41e3-a156-3bc5dc3db317" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_f3c562d5-1103-470a-80a3-5fd11bd57c9b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_ca1ba3bf-4f00-41e3-a156-3bc5dc3db317" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_3fdadf69-2a59-4cb1-920e-5f211387befa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_f3c562d5-1103-470a-80a3-5fd11bd57c9b" xlink:to="loc_us-gaap_Revenues_3fdadf69-2a59-4cb1-920e-5f211387befa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_705a0ae8-9580-4ff9-b1b2-eba2f5dcd5ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_f3c562d5-1103-470a-80a3-5fd11bd57c9b" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_705a0ae8-9580-4ff9-b1b2-eba2f5dcd5ba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_3a1dbb12-0cfa-4327-861f-dda149ee62e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_705a0ae8-9580-4ff9-b1b2-eba2f5dcd5ba" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_3a1dbb12-0cfa-4327-861f-dda149ee62e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3a1dbb12-0cfa-4327-861f-dda149ee62e9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3a1dbb12-0cfa-4327-861f-dda149ee62e9" xlink:to="loc_us-gaap_SegmentDomain_3a1dbb12-0cfa-4327-861f-dda149ee62e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9447573d-2818-41c3-8402-6e3529f8e680" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3a1dbb12-0cfa-4327-861f-dda149ee62e9" xlink:to="loc_us-gaap_SegmentDomain_9447573d-2818-41c3-8402-6e3529f8e680" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_1bddf175-08a2-4aa8-8822-9e2dc7aa5f65" xlink:href="bkh-20210930.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9447573d-2818-41c3-8402-6e3529f8e680" xlink:to="loc_bkh_ElectricUtilitiesMember_1bddf175-08a2-4aa8-8822-9e2dc7aa5f65" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_5f714a88-ac93-4bd3-a7c2-d3473a8782e0" xlink:href="bkh-20210930.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9447573d-2818-41c3-8402-6e3529f8e680" xlink:to="loc_bkh_GasUtilitiesMember_5f714a88-ac93-4bd3-a7c2-d3473a8782e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PowerGenerationMember_d565ad61-5edf-4c39-8565-449c8bcc9779" xlink:href="bkh-20210930.xsd#bkh_PowerGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9447573d-2818-41c3-8402-6e3529f8e680" xlink:to="loc_bkh_PowerGenerationMember_d565ad61-5edf-4c39-8565-449c8bcc9779" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MiningMember_ce3775d6-cf0e-43f4-b46d-02a32ecd6cfa" xlink:href="bkh-20210930.xsd#bkh_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9447573d-2818-41c3-8402-6e3529f8e680" xlink:to="loc_bkh_MiningMember_ce3775d6-cf0e-43f4-b46d-02a32ecd6cfa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_c4ef4e17-3192-4f6c-8666-b0602f7a9d56" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_705a0ae8-9580-4ff9-b1b2-eba2f5dcd5ba" xlink:to="loc_srt_ConsolidationItemsAxis_c4ef4e17-3192-4f6c-8666-b0602f7a9d56" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_c4ef4e17-3192-4f6c-8666-b0602f7a9d56_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_c4ef4e17-3192-4f6c-8666-b0602f7a9d56" xlink:to="loc_srt_ConsolidationItemsDomain_c4ef4e17-3192-4f6c-8666-b0602f7a9d56_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_405e569a-fc13-4e95-af10-2a35dba9d6d5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_c4ef4e17-3192-4f6c-8666-b0602f7a9d56" xlink:to="loc_srt_ConsolidationItemsDomain_405e569a-fc13-4e95-af10-2a35dba9d6d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_8df1edf6-8831-4fe1-b7fb-20895ce86baf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_405e569a-fc13-4e95-af10-2a35dba9d6d5" xlink:to="loc_us-gaap_IntersegmentEliminationMember_8df1edf6-8831-4fe1-b7fb-20895ce86baf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_3213f298-7927-465d-9b2f-4346f7589f26" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_705a0ae8-9580-4ff9-b1b2-eba2f5dcd5ba" xlink:to="loc_srt_MajorCustomersAxis_3213f298-7927-465d-9b2f-4346f7589f26" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_3213f298-7927-465d-9b2f-4346f7589f26_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_3213f298-7927-465d-9b2f-4346f7589f26" xlink:to="loc_srt_NameOfMajorCustomerDomain_3213f298-7927-465d-9b2f-4346f7589f26_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_99ab7d58-54f8-40a5-8c97-c1c291cc5fae" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_3213f298-7927-465d-9b2f-4346f7589f26" xlink:to="loc_srt_NameOfMajorCustomerDomain_99ab7d58-54f8-40a5-8c97-c1c291cc5fae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_RetailElectricNaturalGasandCoalMember_5ccfc09a-88b7-4493-a0bd-8c379ec6404b" xlink:href="bkh-20210930.xsd#bkh_RetailElectricNaturalGasandCoalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_99ab7d58-54f8-40a5-8c97-c1c291cc5fae" xlink:to="loc_bkh_RetailElectricNaturalGasandCoalMember_5ccfc09a-88b7-4493-a0bd-8c379ec6404b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_TransportationMember_312f2e30-6e53-4100-a5ce-0e15f1f8b5b0" xlink:href="bkh-20210930.xsd#bkh_TransportationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_99ab7d58-54f8-40a5-8c97-c1c291cc5fae" xlink:to="loc_bkh_TransportationMember_312f2e30-6e53-4100-a5ce-0e15f1f8b5b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WholesaleMember_5491e96f-08b4-4e21-b2d0-76e3920db934" xlink:href="bkh-20210930.xsd#bkh_WholesaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_99ab7d58-54f8-40a5-8c97-c1c291cc5fae" xlink:to="loc_bkh_WholesaleMember_5491e96f-08b4-4e21-b2d0-76e3920db934" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MarketOffSystemSalesMember_05e33f1f-cc67-4aaa-8160-5720e7680938" xlink:href="bkh-20210930.xsd#bkh_MarketOffSystemSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_99ab7d58-54f8-40a5-8c97-c1c291cc5fae" xlink:to="loc_bkh_MarketOffSystemSalesMember_05e33f1f-cc67-4aaa-8160-5720e7680938" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_TransmissionOtherMember_afb7b128-5d99-4187-947a-7c2325952410" xlink:href="bkh-20210930.xsd#bkh_TransmissionOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_99ab7d58-54f8-40a5-8c97-c1c291cc5fae" xlink:to="loc_bkh_TransmissionOtherMember_afb7b128-5d99-4187-947a-7c2325952410" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_d29c86b2-9b3a-4a78-84f2-363278d4e52a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_705a0ae8-9580-4ff9-b1b2-eba2f5dcd5ba" xlink:to="loc_srt_ProductOrServiceAxis_d29c86b2-9b3a-4a78-84f2-363278d4e52a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_d29c86b2-9b3a-4a78-84f2-363278d4e52a_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_d29c86b2-9b3a-4a78-84f2-363278d4e52a" xlink:to="loc_srt_ProductsAndServicesDomain_d29c86b2-9b3a-4a78-84f2-363278d4e52a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_de93117d-7afa-4088-a871-d41d542f947a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_d29c86b2-9b3a-4a78-84f2-363278d4e52a" xlink:to="loc_srt_ProductsAndServicesDomain_de93117d-7afa-4088-a871-d41d542f947a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherMember_f2808bb4-a7cd-4968-a940-93d1ab52c841" xlink:href="bkh-20210930.xsd#bkh_OtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_de93117d-7afa-4088-a871-d41d542f947a" xlink:to="loc_bkh_OtherMember_f2808bb4-a7cd-4968-a940-93d1ab52c841" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_3724a6e6-b1dd-4968-aee1-7fe17be54fcc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_705a0ae8-9580-4ff9-b1b2-eba2f5dcd5ba" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_3724a6e6-b1dd-4968-aee1-7fe17be54fcc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3724a6e6-b1dd-4968-aee1-7fe17be54fcc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_3724a6e6-b1dd-4968-aee1-7fe17be54fcc" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3724a6e6-b1dd-4968-aee1-7fe17be54fcc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_093bbaad-7e48-40b0-bff4-e00d7d837377" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_3724a6e6-b1dd-4968-aee1-7fe17be54fcc" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_093bbaad-7e48-40b0-bff4-e00d7d837377" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_14649b7a-426d-4156-932d-484a3c2ba2be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_093bbaad-7e48-40b0-bff4-e00d7d837377" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_14649b7a-426d-4156-932d-484a3c2ba2be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_a2facc36-1450-41d6-a042-5890d65fa3ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_093bbaad-7e48-40b0-bff4-e00d7d837377" xlink:to="loc_us-gaap_TransferredOverTimeMember_a2facc36-1450-41d6-a042-5890d65fa3ed" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingScheduleofShorttermDebtandNarrativeDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FinancingScheduleofShorttermDebtandNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingScheduleofShorttermDebtandNarrativeDetails" xlink:type="extended" id="ice722fcf108f434eacaa684c98866191_FinancingScheduleofShorttermDebtandNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_1f311747-36c7-4b16-a397-e5df2c51f988" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_ef6fd11c-27f0-4905-8dae-776b6244fe65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_1f311747-36c7-4b16-a397-e5df2c51f988" xlink:to="loc_us-gaap_ShortTermBorrowings_ef6fd11c-27f0-4905-8dae-776b6244fe65" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_f7401661-8f8c-464b-83d1-bb7ed91a1e12" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_1f311747-36c7-4b16-a397-e5df2c51f988" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_f7401661-8f8c-464b-83d1-bb7ed91a1e12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_960d3469-251c-411c-a8d7-12b107b00ff8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_1f311747-36c7-4b16-a397-e5df2c51f988" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_960d3469-251c-411c-a8d7-12b107b00ff8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_9b889e35-465d-4a2b-a3a1-da35a2a432c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_960d3469-251c-411c-a8d7-12b107b00ff8" xlink:to="loc_us-gaap_CreditFacilityAxis_9b889e35-465d-4a2b-a3a1-da35a2a432c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_9b889e35-465d-4a2b-a3a1-da35a2a432c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_9b889e35-465d-4a2b-a3a1-da35a2a432c7" xlink:to="loc_us-gaap_CreditFacilityDomain_9b889e35-465d-4a2b-a3a1-da35a2a432c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_cabb34dd-5ed2-49f8-b536-207dcd09d88b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_9b889e35-465d-4a2b-a3a1-da35a2a432c7" xlink:to="loc_us-gaap_CreditFacilityDomain_cabb34dd-5ed2-49f8-b536-207dcd09d88b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_e71d6fa7-fbbb-49cd-8c9e-fd65ca134d32" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_cabb34dd-5ed2-49f8-b536-207dcd09d88b" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_e71d6fa7-fbbb-49cd-8c9e-fd65ca134d32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_227bddcf-cbfa-44d0-a675-32767b9b2404" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_960d3469-251c-411c-a8d7-12b107b00ff8" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_227bddcf-cbfa-44d0-a675-32767b9b2404" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_227bddcf-cbfa-44d0-a675-32767b9b2404_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_227bddcf-cbfa-44d0-a675-32767b9b2404" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_227bddcf-cbfa-44d0-a675-32767b9b2404_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_b1b324fc-4463-452b-a7bc-af650ecf27f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_227bddcf-cbfa-44d0-a675-32767b9b2404" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_b1b324fc-4463-452b-a7bc-af650ecf27f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_febfa4cf-1ff6-4e97-ab39-9004b39cd93e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_b1b324fc-4463-452b-a7bc-af650ecf27f4" xlink:to="loc_us-gaap_CommercialPaperMember_febfa4cf-1ff6-4e97-ab39-9004b39cd93e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingRevolvingCreditFacilityandCPProgramDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FinancingRevolvingCreditFacilityandCPProgramDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingRevolvingCreditFacilityandCPProgramDetails" xlink:type="extended" id="i6f9498d8af5d4961b3471489e5076ee1_FinancingRevolvingCreditFacilityandCPProgramDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ad382ca4-3687-445f-90e0-ee0eb49d7f44" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ad382ca4-3687-445f-90e0-ee0eb49d7f44" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NumberOfOneYearExtensionOptions_ea72909d-c65b-4bf7-8b70-b317437940a9" xlink:href="bkh-20210930.xsd#bkh_NumberOfOneYearExtensionOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_bkh_NumberOfOneYearExtensionOptions_ea72909d-c65b-4bf7-8b70-b317437940a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_e0bdd476-56ed-4be7-9bd2-149cec93bb90" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_us-gaap_DebtInstrumentTerm_e0bdd476-56ed-4be7-9bd2-149cec93bb90" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd_5173b211-c921-4854-8232-b1baf240f7ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd_5173b211-c921-4854-8232-b1baf240f7ae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_9300f8d6-0f0a-4494-a77c-957afcc5837c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_9300f8d6-0f0a-4494-a77c-957afcc5837c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NetPaymentsBorrowingsOfRevolvingCreditFacilityAndCommercialPaperProgram_00e35442-5100-40ac-812d-5900f9bb55e1" xlink:href="bkh-20210930.xsd#bkh_NetPaymentsBorrowingsOfRevolvingCreditFacilityAndCommercialPaperProgram"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_bkh_NetPaymentsBorrowingsOfRevolvingCreditFacilityAndCommercialPaperProgram_00e35442-5100-40ac-812d-5900f9bb55e1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_b6122961-ab72-4bb4-b268-b0c640095e01" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_b6122961-ab72-4bb4-b268-b0c640095e01" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_2e51f88a-941c-4f04-86f8-46642faf196b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_97a6d27e-423c-4ab9-98ec-9e9a9d25ee7c" xlink:to="loc_us-gaap_StatementTable_2e51f88a-941c-4f04-86f8-46642faf196b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_5cc92463-926a-4aec-8543-175beb3a071f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2e51f88a-941c-4f04-86f8-46642faf196b" xlink:to="loc_us-gaap_CreditFacilityAxis_5cc92463-926a-4aec-8543-175beb3a071f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_5cc92463-926a-4aec-8543-175beb3a071f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_5cc92463-926a-4aec-8543-175beb3a071f" xlink:to="loc_us-gaap_CreditFacilityDomain_5cc92463-926a-4aec-8543-175beb3a071f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_4746e05b-13f5-46a2-9cd9-a21caba6ec2c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_5cc92463-926a-4aec-8543-175beb3a071f" xlink:to="loc_us-gaap_CreditFacilityDomain_4746e05b-13f5-46a2-9cd9-a21caba6ec2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_d811983d-3f26-4ba6-9c0f-06dafccf5118" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_4746e05b-13f5-46a2-9cd9-a21caba6ec2c" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_d811983d-3f26-4ba6-9c0f-06dafccf5118" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_f8993770-62b1-4807-bbd6-064309fecd77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2e51f88a-941c-4f04-86f8-46642faf196b" xlink:to="loc_us-gaap_VariableRateAxis_f8993770-62b1-4807-bbd6-064309fecd77" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_f8993770-62b1-4807-bbd6-064309fecd77_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_f8993770-62b1-4807-bbd6-064309fecd77" xlink:to="loc_us-gaap_VariableRateDomain_f8993770-62b1-4807-bbd6-064309fecd77_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_3a924c3b-6901-4b21-87a4-b33fa17ce03d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_f8993770-62b1-4807-bbd6-064309fecd77" xlink:to="loc_us-gaap_VariableRateDomain_3a924c3b-6901-4b21-87a4-b33fa17ce03d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_bcf5af8b-8068-4be9-96ef-14ab4b905447" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_3a924c3b-6901-4b21-87a4-b33fa17ce03d" xlink:to="loc_us-gaap_BaseRateMember_bcf5af8b-8068-4be9-96ef-14ab4b905447" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EurodollarMember_52f357ff-b4e2-43b9-a8b5-6a122394f305" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EurodollarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_3a924c3b-6901-4b21-87a4-b33fa17ce03d" xlink:to="loc_us-gaap_EurodollarMember_52f357ff-b4e2-43b9-a8b5-6a122394f305" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_64bca599-4944-4b10-a6d8-07a1e6215b3b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_3a924c3b-6901-4b21-87a4-b33fa17ce03d" xlink:to="loc_us-gaap_LetterOfCreditMember_64bca599-4944-4b10-a6d8-07a1e6215b3b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_d14edf29-f088-4a53-a5db-1044d7746c6d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_2e51f88a-941c-4f04-86f8-46642faf196b" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_d14edf29-f088-4a53-a5db-1044d7746c6d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_d14edf29-f088-4a53-a5db-1044d7746c6d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_d14edf29-f088-4a53-a5db-1044d7746c6d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_d14edf29-f088-4a53-a5db-1044d7746c6d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_ed1e379a-3c3f-44c4-8dcb-d78f7eb1a1d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_d14edf29-f088-4a53-a5db-1044d7746c6d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_ed1e379a-3c3f-44c4-8dcb-d78f7eb1a1d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_03b75333-7f4b-4df8-a164-3d0b3b31082b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_ed1e379a-3c3f-44c4-8dcb-d78f7eb1a1d2" xlink:to="loc_us-gaap_CommercialPaperMember_03b75333-7f4b-4df8-a164-3d0b3b31082b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingTermLoanDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FinancingTermLoanDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingTermLoanDetails" xlink:type="extended" id="i6dce5c52d1e94afba6244c1ed9b2626a_FinancingTermLoanDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_4d5bb2b9-797f-405c-a297-905b7662e147" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_34e7e67d-79f6-4f34-b6ff-9b9eff4e14de" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4d5bb2b9-797f-405c-a297-905b7662e147" xlink:to="loc_us-gaap_DebtInstrumentTerm_34e7e67d-79f6-4f34-b6ff-9b9eff4e14de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_14fb07d5-d3ab-4e8a-93dd-4edea939029c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4d5bb2b9-797f-405c-a297-905b7662e147" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_14fb07d5-d3ab-4e8a-93dd-4edea939029c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_6d61b312-20b5-4669-bab8-94e6f6b85749" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4d5bb2b9-797f-405c-a297-905b7662e147" xlink:to="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_6d61b312-20b5-4669-bab8-94e6f6b85749" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfOtherShortTermDebt_be7817c7-3378-4e98-834d-8877a22d1fa0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfOtherShortTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4d5bb2b9-797f-405c-a297-905b7662e147" xlink:to="loc_us-gaap_RepaymentsOfOtherShortTermDebt_be7817c7-3378-4e98-834d-8877a22d1fa0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_051546e9-47ab-4efa-a53a-63c6a6daef00" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_4d5bb2b9-797f-405c-a297-905b7662e147" xlink:to="loc_us-gaap_StatementTable_051546e9-47ab-4efa-a53a-63c6a6daef00" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_0897e9f7-b197-4ed6-92b6-c0e963a33c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_051546e9-47ab-4efa-a53a-63c6a6daef00" xlink:to="loc_us-gaap_DebtInstrumentAxis_0897e9f7-b197-4ed6-92b6-c0e963a33c3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0897e9f7-b197-4ed6-92b6-c0e963a33c3b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_0897e9f7-b197-4ed6-92b6-c0e963a33c3b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0897e9f7-b197-4ed6-92b6-c0e963a33c3b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4b3e77e6-9940-4e1a-b91f-52f088b04bab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_0897e9f7-b197-4ed6-92b6-c0e963a33c3b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4b3e77e6-9940-4e1a-b91f-52f088b04bab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SeniorUnsecuredNotesDue2021Member_52ced1ae-0b4a-49d5-ac67-1268e540b7d6" xlink:href="bkh-20210930.xsd#bkh_SeniorUnsecuredNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_4b3e77e6-9940-4e1a-b91f-52f088b04bab" xlink:to="loc_bkh_SeniorUnsecuredNotesDue2021Member_52ced1ae-0b4a-49d5-ac67-1268e540b7d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_11b3aa4b-092c-4a7a-8cff-2ac1487838d8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_051546e9-47ab-4efa-a53a-63c6a6daef00" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_11b3aa4b-092c-4a7a-8cff-2ac1487838d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_11b3aa4b-092c-4a7a-8cff-2ac1487838d8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_11b3aa4b-092c-4a7a-8cff-2ac1487838d8" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_11b3aa4b-092c-4a7a-8cff-2ac1487838d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_40a8ef14-152e-47be-a536-49693ebccf25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_11b3aa4b-092c-4a7a-8cff-2ac1487838d8" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_40a8ef14-152e-47be-a536-49693ebccf25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_6a73f0cd-c823-4e7f-bdda-ff23451551e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_40a8ef14-152e-47be-a536-49693ebccf25" xlink:to="loc_us-gaap_LineOfCreditMember_6a73f0cd-c823-4e7f-bdda-ff23451551e3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingLongtermdebtDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FinancingLongtermdebtDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingLongtermdebtDetails" xlink:type="extended" id="i51b3e25bff83471686dab806910a58e6_FinancingLongtermdebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ddbcedec-702f-4fbb-b11f-f5f885f44637" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_e904fbd0-e19c-4b89-8a5d-39de8eb87221" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ddbcedec-702f-4fbb-b11f-f5f885f44637" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_e904fbd0-e19c-4b89-8a5d-39de8eb87221" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_24fcfee5-eca6-4d5b-9fc6-f3a38e3cbd1f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ddbcedec-702f-4fbb-b11f-f5f885f44637" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_24fcfee5-eca6-4d5b-9fc6-f3a38e3cbd1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_a694341f-e78d-42a4-ae9e-65ad2c16d177" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ddbcedec-702f-4fbb-b11f-f5f885f44637" xlink:to="loc_us-gaap_DebtInstrumentTerm_a694341f-e78d-42a4-ae9e-65ad2c16d177" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_f16518c4-9bd5-4cf4-8316-5131046caee7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ddbcedec-702f-4fbb-b11f-f5f885f44637" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_f16518c4-9bd5-4cf4-8316-5131046caee7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_63daabdd-f51c-4f85-b4ab-37da114c8c48" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_ddbcedec-702f-4fbb-b11f-f5f885f44637" xlink:to="loc_us-gaap_StatementTable_63daabdd-f51c-4f85-b4ab-37da114c8c48" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_0af67cd5-1a3f-457c-bfa5-29468478869d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_63daabdd-f51c-4f85-b4ab-37da114c8c48" xlink:to="loc_us-gaap_DebtInstrumentAxis_0af67cd5-1a3f-457c-bfa5-29468478869d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0af67cd5-1a3f-457c-bfa5-29468478869d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_0af67cd5-1a3f-457c-bfa5-29468478869d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0af67cd5-1a3f-457c-bfa5-29468478869d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_e8cc5c2a-f397-4a03-a871-2ee1af966370" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_0af67cd5-1a3f-457c-bfa5-29468478869d" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_e8cc5c2a-f397-4a03-a871-2ee1af966370" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SeniorUnsecuredNotesDue2024Member_b1c0c499-e850-4be3-a1cb-975a84a4f1fa" xlink:href="bkh-20210930.xsd#bkh_SeniorUnsecuredNotesDue2024Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_e8cc5c2a-f397-4a03-a871-2ee1af966370" xlink:to="loc_bkh_SeniorUnsecuredNotesDue2024Member_b1c0c499-e850-4be3-a1cb-975a84a4f1fa" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingDebtCovenantsDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FinancingDebtCovenantsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingDebtCovenantsDetails" xlink:type="extended" id="i55b9986ac0e74db08e98d00672d8d050_FinancingDebtCovenantsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_57cae949-61c6-48ee-966d-c2742dafce88" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DebtInstrumentConsolidatedIndebtednessToCapitalizationRatioRequirementForTheNextFiscalYear_6ca00fb1-3d4d-4111-815c-746d07b1bfb2" xlink:href="bkh-20210930.xsd#bkh_DebtInstrumentConsolidatedIndebtednessToCapitalizationRatioRequirementForTheNextFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_57cae949-61c6-48ee-966d-c2742dafce88" xlink:to="loc_bkh_DebtInstrumentConsolidatedIndebtednessToCapitalizationRatioRequirementForTheNextFiscalYear_6ca00fb1-3d4d-4111-815c-746d07b1bfb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RatioOfIndebtednessToNetCapital1_75aaef55-0e82-4ee2-93bd-57950d7231e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RatioOfIndebtednessToNetCapital1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_57cae949-61c6-48ee-966d-c2742dafce88" xlink:to="loc_us-gaap_RatioOfIndebtednessToNetCapital1_75aaef55-0e82-4ee2-93bd-57950d7231e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_bcaf1b2e-dd77-460f-a573-831077d3e283" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_57cae949-61c6-48ee-966d-c2742dafce88" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_bcaf1b2e-dd77-460f-a573-831077d3e283" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_4633fa67-4a60-49be-8d6a-bbe49c41506e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_bcaf1b2e-dd77-460f-a573-831077d3e283" xlink:to="loc_srt_RangeAxis_4633fa67-4a60-49be-8d6a-bbe49c41506e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4633fa67-4a60-49be-8d6a-bbe49c41506e_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_4633fa67-4a60-49be-8d6a-bbe49c41506e" xlink:to="loc_srt_RangeMember_4633fa67-4a60-49be-8d6a-bbe49c41506e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4346ed3b-f3cd-4afa-98d4-d79f8fef9829" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_4633fa67-4a60-49be-8d6a-bbe49c41506e" xlink:to="loc_srt_RangeMember_4346ed3b-f3cd-4afa-98d4-d79f8fef9829" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_0d24e8b5-fd96-470f-9cd5-8f29e4f88dcb" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_4346ed3b-f3cd-4afa-98d4-d79f8fef9829" xlink:to="loc_srt_MaximumMember_0d24e8b5-fd96-470f-9cd5-8f29e4f88dcb" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingEquityDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FinancingEquityDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingEquityDetails" xlink:type="extended" id="i9f2fef75c549477ab7b911eba7d42723_FinancingEquityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_efd4bb7f-823a-4095-af65-86988d02bab0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AtTheMarketEquityOfferingProgramSharesIssued_9d15a095-110a-45d2-9d1b-5364aa0a5ef0" xlink:href="bkh-20210930.xsd#bkh_AtTheMarketEquityOfferingProgramSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_efd4bb7f-823a-4095-af65-86988d02bab0" xlink:to="loc_bkh_AtTheMarketEquityOfferingProgramSharesIssued_9d15a095-110a-45d2-9d1b-5364aa0a5ef0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AtTheMarketEquityProgramProceedsfromSaleofStock_a34a1217-1116-4114-8b93-1d28f4bdb5aa" xlink:href="bkh-20210930.xsd#bkh_AtTheMarketEquityProgramProceedsfromSaleofStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_efd4bb7f-823a-4095-af65-86988d02bab0" xlink:to="loc_bkh_AtTheMarketEquityProgramProceedsfromSaleofStock_a34a1217-1116-4114-8b93-1d28f4bdb5aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AtTheMarketEquityProgramStockIssuedIssuanceCosts_2cc27f53-ef83-499e-89c4-806c35bcecfd" xlink:href="bkh-20210930.xsd#bkh_AtTheMarketEquityProgramStockIssuedIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_efd4bb7f-823a-4095-af65-86988d02bab0" xlink:to="loc_bkh_AtTheMarketEquityProgramStockIssuedIssuanceCosts_2cc27f53-ef83-499e-89c4-806c35bcecfd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_5633943e-5d47-4861-89f6-95bfbde9faa8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_efd4bb7f-823a-4095-af65-86988d02bab0" xlink:to="loc_us-gaap_StatementTable_5633943e-5d47-4861-89f6-95bfbde9faa8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c92d38c2-ac24-429d-a299-39fe41933136" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5633943e-5d47-4861-89f6-95bfbde9faa8" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c92d38c2-ac24-429d-a299-39fe41933136" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c92d38c2-ac24-429d-a299-39fe41933136_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c92d38c2-ac24-429d-a299-39fe41933136" xlink:to="loc_us-gaap_EquityComponentDomain_c92d38c2-ac24-429d-a299-39fe41933136_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_00827530-802e-4cad-85d6-9d8ca5d4888e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c92d38c2-ac24-429d-a299-39fe41933136" xlink:to="loc_us-gaap_EquityComponentDomain_00827530-802e-4cad-85d6-9d8ca5d4888e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_5cd38027-2324-4458-888e-c4ec7eaa57c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_00827530-802e-4cad-85d6-9d8ca5d4888e" xlink:to="loc_us-gaap_CommonStockMember_5cd38027-2324-4458-888e-c4ec7eaa57c4" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EarningsPerShareAntidilutivesharesDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#EarningsPerShareAntidilutivesharesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EarningsPerShareAntidilutivesharesDetails" xlink:type="extended" id="if10252d0b29b46b48c1c77658cfffd8e_EarningsPerShareAntidilutivesharesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_1ac5e158-64ea-4dee-971b-e8b1c6c1413a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d37534bc-9048-4807-963b-4a5d5b2608b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_1ac5e158-64ea-4dee-971b-e8b1c6c1413a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d37534bc-9048-4807-963b-4a5d5b2608b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_dad7eecf-b5e4-405b-8585-569f0b293dc2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_1ac5e158-64ea-4dee-971b-e8b1c6c1413a" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_dad7eecf-b5e4-405b-8585-569f0b293dc2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_65fd229e-a5f0-476e-b16c-fe0a2cfce60d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_dad7eecf-b5e4-405b-8585-569f0b293dc2" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_65fd229e-a5f0-476e-b16c-fe0a2cfce60d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_65fd229e-a5f0-476e-b16c-fe0a2cfce60d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_65fd229e-a5f0-476e-b16c-fe0a2cfce60d" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_65fd229e-a5f0-476e-b16c-fe0a2cfce60d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c0b71d71-c666-407d-9405-1f13afea8b33" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_65fd229e-a5f0-476e-b16c-fe0a2cfce60d" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c0b71d71-c666-407d-9405-1f13afea8b33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockCompensationPlanMember_a49e5de8-a755-4e49-9dc6-727de52a0724" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockCompensationPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c0b71d71-c666-407d-9405-1f13afea8b33" xlink:to="loc_us-gaap_StockCompensationPlanMember_a49e5de8-a755-4e49-9dc6-727de52a0724" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_c4faf20c-bf59-47f1-83d7-8f6b703786d8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_c0b71d71-c666-407d-9405-1f13afea8b33" xlink:to="loc_us-gaap_RestrictedStockMember_c4faf20c-bf59-47f1-83d7-8f6b703786d8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesUtilitiesDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RiskManagementandDerivativesUtilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesUtilitiesDetails" xlink:type="extended" id="i05b74818e6ab4224becf77b00c39f23c_RiskManagementandDerivativesUtilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_847c5cbf-623f-45e5-a48d-f7c922e66276" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmount_e96f5961-33d5-447d-b4f1-9256582fa426" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_847c5cbf-623f-45e5-a48d-f7c922e66276" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmount_e96f5961-33d5-447d-b4f1-9256582fa426" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeRemainingMaturity1_44534fcf-4839-42e0-a663-7d94373a48d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeRemainingMaturity1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_847c5cbf-623f-45e5-a48d-f7c922e66276" xlink:to="loc_us-gaap_DerivativeRemainingMaturity1_44534fcf-4839-42e0-a663-7d94373a48d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAlreadyPostedAggregateFairValue_47e75742-8137-468b-b90d-060a9fbfb261" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollateralAlreadyPostedAggregateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_847c5cbf-623f-45e5-a48d-f7c922e66276" xlink:to="loc_us-gaap_CollateralAlreadyPostedAggregateFairValue_47e75742-8137-468b-b90d-060a9fbfb261" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_9daae83b-7eab-4171-9b79-3ba80ce3bb1e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_847c5cbf-623f-45e5-a48d-f7c922e66276" xlink:to="loc_us-gaap_DerivativeTable_9daae83b-7eab-4171-9b79-3ba80ce3bb1e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyAxis_78f9600d-5a01-4a34-afa4-56247d40d4c0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EnergyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9daae83b-7eab-4171-9b79-3ba80ce3bb1e" xlink:to="loc_srt_EnergyAxis_78f9600d-5a01-4a34-afa4-56247d40d4c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_78f9600d-5a01-4a34-afa4-56247d40d4c0_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_EnergyAxis_78f9600d-5a01-4a34-afa4-56247d40d4c0" xlink:to="loc_srt_EnergyDomain_78f9600d-5a01-4a34-afa4-56247d40d4c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_3304d30f-c3f2-4292-b630-089a3ef09db4" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_EnergyAxis_78f9600d-5a01-4a34-afa4-56247d40d4c0" xlink:to="loc_srt_EnergyDomain_3304d30f-c3f2-4292-b630-089a3ef09db4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NaturalGasDistributionMember_404d40bb-cbda-4383-884a-5ebffdc7d3ad" xlink:href="bkh-20210930.xsd#bkh_NaturalGasDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_3304d30f-c3f2-4292-b630-089a3ef09db4" xlink:to="loc_bkh_NaturalGasDistributionMember_404d40bb-cbda-4383-884a-5ebffdc7d3ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ElectricityMember_03ce0699-a71d-4e30-8284-a299f256fb28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ElectricityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_3304d30f-c3f2-4292-b630-089a3ef09db4" xlink:to="loc_us-gaap_ElectricityMember_03ce0699-a71d-4e30-8284-a299f256fb28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_f7889d9b-fc99-4ef9-b28f-9f9e7fa2f73e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9daae83b-7eab-4171-9b79-3ba80ce3bb1e" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_f7889d9b-fc99-4ef9-b28f-9f9e7fa2f73e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_f7889d9b-fc99-4ef9-b28f-9f9e7fa2f73e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_f7889d9b-fc99-4ef9-b28f-9f9e7fa2f73e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_f7889d9b-fc99-4ef9-b28f-9f9e7fa2f73e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_f7889d9b-fc99-4ef9-b28f-9f9e7fa2f73e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FutureMember_6bf3422c-08d0-43d7-8b14-3cddfdb81e8d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FutureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:to="loc_us-gaap_FutureMember_6bf3422c-08d0-43d7-8b14-3cddfdb81e8d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityOptionMember_4680ba73-c4cb-4952-839e-8a108887cbe2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:to="loc_us-gaap_CommodityOptionMember_4680ba73-c4cb-4952-839e-8a108887cbe2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BasisSwapMember_97df3454-bb63-4d8e-a740-827fc95435d6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BasisSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:to="loc_us-gaap_BasisSwapMember_97df3454-bb63-4d8e-a740-827fc95435d6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FixedforFloatSwapsPurchasedMember_0b8607be-1eec-4eeb-8e97-65c0944c2e30" xlink:href="bkh-20210930.xsd#bkh_FixedforFloatSwapsPurchasedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:to="loc_bkh_FixedforFloatSwapsPurchasedMember_0b8607be-1eec-4eeb-8e97-65c0944c2e30" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NaturalGasPhysicalPurchasesMember_b239ae62-a5c4-4857-8bf2-02ef0c807af5" xlink:href="bkh-20210930.xsd#bkh_NaturalGasPhysicalPurchasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:to="loc_bkh_NaturalGasPhysicalPurchasesMember_b239ae62-a5c4-4857-8bf2-02ef0c807af5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnergyRelatedDerivativeMember_40a90186-0ad8-4372-a465-609ba6cd8ed4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EnergyRelatedDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:to="loc_us-gaap_EnergyRelatedDerivativeMember_40a90186-0ad8-4372-a465-609ba6cd8ed4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_a5f9d1fd-6239-49fa-a653-9a16190a3239" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_906ca95a-e132-412e-8d13-2ed6fcb62411" xlink:to="loc_us-gaap_CommodityContractMember_a5f9d1fd-6239-49fa-a653-9a16190a3239" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_6ece1cfb-1197-45c0-8719-4ec94a8fad19" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9daae83b-7eab-4171-9b79-3ba80ce3bb1e" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_6ece1cfb-1197-45c0-8719-4ec94a8fad19" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_6ece1cfb-1197-45c0-8719-4ec94a8fad19_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_6ece1cfb-1197-45c0-8719-4ec94a8fad19" xlink:to="loc_us-gaap_HedgingRelationshipDomain_6ece1cfb-1197-45c0-8719-4ec94a8fad19_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_09a6b91c-62db-485d-b186-b4c1ddd2482b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_6ece1cfb-1197-45c0-8719-4ec94a8fad19" xlink:to="loc_us-gaap_HedgingRelationshipDomain_09a6b91c-62db-485d-b186-b4c1ddd2482b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_82a55c6f-8cbf-4785-80b8-c85e1d2d2c86" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_09a6b91c-62db-485d-b186-b4c1ddd2482b" xlink:to="loc_us-gaap_CashFlowHedgingMember_82a55c6f-8cbf-4785-80b8-c85e1d2d2c86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionAxis_bbfc7023-6adc-4645-80d7-d49b6342c8b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PositionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9daae83b-7eab-4171-9b79-3ba80ce3bb1e" xlink:to="loc_us-gaap_PositionAxis_bbfc7023-6adc-4645-80d7-d49b6342c8b5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_bbfc7023-6adc-4645-80d7-d49b6342c8b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PositionAxis_bbfc7023-6adc-4645-80d7-d49b6342c8b5" xlink:to="loc_us-gaap_PositionDomain_bbfc7023-6adc-4645-80d7-d49b6342c8b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_8ec75a32-75c7-4b4b-baad-62e5184d8875" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PositionAxis_bbfc7023-6adc-4645-80d7-d49b6342c8b5" xlink:to="loc_us-gaap_PositionDomain_8ec75a32-75c7-4b4b-baad-62e5184d8875" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongMember_4dbcdf65-2d89-4bf8-8a36-f04890f4c51e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PositionDomain_8ec75a32-75c7-4b4b-baad-62e5184d8875" xlink:to="loc_us-gaap_LongMember_4dbcdf65-2d89-4bf8-8a36-f04890f4c51e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails" xlink:type="extended" id="ifab4287ddf0d4a57a51310ff820b09fe_RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_ad6e4120-d300-487b-94aa-c54adc4c72f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgeAssetsAtFairValue_1568b68a-24ad-4a44-bfe4-c7753fc7d5c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueHedgeAssetsAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_ad6e4120-d300-487b-94aa-c54adc4c72f3" xlink:to="loc_us-gaap_FairValueHedgeAssetsAtFairValue_1568b68a-24ad-4a44-bfe4-c7753fc7d5c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgeLiabilitiesAtFairValue_32ed1793-68f7-46d0-a5a5-5000c678b46f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueHedgeLiabilitiesAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_ad6e4120-d300-487b-94aa-c54adc4c72f3" xlink:to="loc_us-gaap_FairValueHedgeLiabilitiesAtFairValue_32ed1793-68f7-46d0-a5a5-5000c678b46f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgesAtFairValueNet_e8cbcefc-6cde-498f-ac19-ee02a85b2195" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueHedgesAtFairValueNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_ad6e4120-d300-487b-94aa-c54adc4c72f3" xlink:to="loc_us-gaap_FairValueHedgesAtFairValueNet_e8cbcefc-6cde-498f-ac19-ee02a85b2195" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b3d14001-9751-4079-b53a-5aeb81700334" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_ad6e4120-d300-487b-94aa-c54adc4c72f3" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b3d14001-9751-4079-b53a-5aeb81700334" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_f647d8f5-cef6-40e6-84a1-9cbff2b16c34" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b3d14001-9751-4079-b53a-5aeb81700334" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_f647d8f5-cef6-40e6-84a1-9cbff2b16c34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_f647d8f5-cef6-40e6-84a1-9cbff2b16c34_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_f647d8f5-cef6-40e6-84a1-9cbff2b16c34" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_f647d8f5-cef6-40e6-84a1-9cbff2b16c34_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_461e6ec8-d8c4-47e4-af21-a4f8287dce24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_f647d8f5-cef6-40e6-84a1-9cbff2b16c34" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_461e6ec8-d8c4-47e4-af21-a4f8287dce24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_7959ca7c-5e09-41c5-b059-26d83d782a52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_461e6ec8-d8c4-47e4-af21-a4f8287dce24" xlink:to="loc_us-gaap_CommodityContractMember_7959ca7c-5e09-41c5-b059-26d83d782a52" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_42a8179a-b4a9-403b-82de-2d68f29a4f24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b3d14001-9751-4079-b53a-5aeb81700334" xlink:to="loc_us-gaap_HedgingDesignationAxis_42a8179a-b4a9-403b-82de-2d68f29a4f24" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_42a8179a-b4a9-403b-82de-2d68f29a4f24_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_42a8179a-b4a9-403b-82de-2d68f29a4f24" xlink:to="loc_us-gaap_HedgingDesignationDomain_42a8179a-b4a9-403b-82de-2d68f29a4f24_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_50689284-9181-4510-944c-155bb9e06167" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_42a8179a-b4a9-403b-82de-2d68f29a4f24" xlink:to="loc_us-gaap_HedgingDesignationDomain_50689284-9181-4510-944c-155bb9e06167" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_3aff45e6-ba8c-4dcf-a34c-0cb9a7575d73" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_50689284-9181-4510-944c-155bb9e06167" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_3aff45e6-ba8c-4dcf-a34c-0cb9a7575d73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_9cea45b9-5ca7-485c-bd12-15537c6f87cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_50689284-9181-4510-944c-155bb9e06167" xlink:to="loc_us-gaap_NondesignatedMember_9cea45b9-5ca7-485c-bd12-15537c6f87cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_14d0b103-743f-4e25-8322-0ef3719910f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_b3d14001-9751-4079-b53a-5aeb81700334" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_14d0b103-743f-4e25-8322-0ef3719910f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_14d0b103-743f-4e25-8322-0ef3719910f6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_14d0b103-743f-4e25-8322-0ef3719910f6" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_14d0b103-743f-4e25-8322-0ef3719910f6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_119f7653-088a-4a13-b6fc-2d5e2fb5bc9b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_14d0b103-743f-4e25-8322-0ef3719910f6" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_119f7653-088a-4a13-b6fc-2d5e2fb5bc9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DerivativeAssetsCurrentMember_5324af8c-a792-46de-94b5-afaae89056e5" xlink:href="bkh-20210930.xsd#bkh_DerivativeAssetsCurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_119f7653-088a-4a13-b6fc-2d5e2fb5bc9b" xlink:to="loc_bkh_DerivativeAssetsCurrentMember_5324af8c-a792-46de-94b5-afaae89056e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DerivativeAssetsNoncurrentMember_f5c1046c-ff48-44b8-afbf-383b7073f031" xlink:href="bkh-20210930.xsd#bkh_DerivativeAssetsNoncurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_119f7653-088a-4a13-b6fc-2d5e2fb5bc9b" xlink:to="loc_bkh_DerivativeAssetsNoncurrentMember_f5c1046c-ff48-44b8-afbf-383b7073f031" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DerivativeLiabilitiesCurrentMember_80318b78-af21-4d81-b786-68fb6245d753" xlink:href="bkh-20210930.xsd#bkh_DerivativeLiabilitiesCurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_119f7653-088a-4a13-b6fc-2d5e2fb5bc9b" xlink:to="loc_bkh_DerivativeLiabilitiesCurrentMember_80318b78-af21-4d81-b786-68fb6245d753" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails" xlink:type="extended" id="i8b531cf909e2487292f83ff4fb4d6f58_RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_a6ecabb0-3e53-4506-ae35-0e60af9b690f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrealizedGainLossOnPriceRiskCashFlowDerivativesBeforeTax_a1b369db-9f2e-4bff-915f-a58dc98a829c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrealizedGainLossOnPriceRiskCashFlowDerivativesBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_a6ecabb0-3e53-4506-ae35-0e60af9b690f" xlink:to="loc_us-gaap_UnrealizedGainLossOnPriceRiskCashFlowDerivativesBeforeTax_a1b369db-9f2e-4bff-915f-a58dc98a829c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_e3ed9891-e53f-4f9b-a3c0-554528650e53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_a6ecabb0-3e53-4506-ae35-0e60af9b690f" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_e3ed9891-e53f-4f9b-a3c0-554528650e53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_c1cadf18-9fcd-4b6c-baad-dbae65a396c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_a6ecabb0-3e53-4506-ae35-0e60af9b690f" xlink:to="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_c1cadf18-9fcd-4b6c-baad-dbae65a396c4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_67c6639a-139a-41a9-82a5-ae4edd8b3be0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_a6ecabb0-3e53-4506-ae35-0e60af9b690f" xlink:to="loc_us-gaap_DerivativeTable_67c6639a-139a-41a9-82a5-ae4edd8b3be0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_ccdd1b79-5c1a-45fc-aa6e-c3f0ede443c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_67c6639a-139a-41a9-82a5-ae4edd8b3be0" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_ccdd1b79-5c1a-45fc-aa6e-c3f0ede443c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_ccdd1b79-5c1a-45fc-aa6e-c3f0ede443c5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_ccdd1b79-5c1a-45fc-aa6e-c3f0ede443c5" xlink:to="loc_us-gaap_HedgingRelationshipDomain_ccdd1b79-5c1a-45fc-aa6e-c3f0ede443c5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_be626fed-0cdb-47f9-8a8e-9b23d2b6598d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_ccdd1b79-5c1a-45fc-aa6e-c3f0ede443c5" xlink:to="loc_us-gaap_HedgingRelationshipDomain_be626fed-0cdb-47f9-8a8e-9b23d2b6598d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_05de623c-ce20-4aac-bf4d-9925148e9491" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_be626fed-0cdb-47f9-8a8e-9b23d2b6598d" xlink:to="loc_us-gaap_CashFlowHedgingMember_05de623c-ce20-4aac-bf4d-9925148e9491" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_b58ad5ff-a7aa-4627-8f31-0b5450453836" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_67c6639a-139a-41a9-82a5-ae4edd8b3be0" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_b58ad5ff-a7aa-4627-8f31-0b5450453836" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_b58ad5ff-a7aa-4627-8f31-0b5450453836_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_b58ad5ff-a7aa-4627-8f31-0b5450453836" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_b58ad5ff-a7aa-4627-8f31-0b5450453836_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ed067f64-1e1f-4b48-9304-3a7260e4e3af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_b58ad5ff-a7aa-4627-8f31-0b5450453836" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ed067f64-1e1f-4b48-9304-3a7260e4e3af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_59f3a4c2-d452-44d5-abf5-094f612a5403" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ed067f64-1e1f-4b48-9304-3a7260e4e3af" xlink:to="loc_us-gaap_InterestRateSwapMember_59f3a4c2-d452-44d5-abf5-094f612a5403" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_9921f309-a209-4dd3-8c32-f5cebc41417b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ed067f64-1e1f-4b48-9304-3a7260e4e3af" xlink:to="loc_us-gaap_CommodityContractMember_9921f309-a209-4dd3-8c32-f5cebc41417b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_InterestRateSwapAndCommodityDerivativeMember_30ad2ef3-cf49-4498-9fcb-2a1fd82fb0c0" xlink:href="bkh-20210930.xsd#bkh_InterestRateSwapAndCommodityDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ed067f64-1e1f-4b48-9304-3a7260e4e3af" xlink:to="loc_bkh_InterestRateSwapAndCommodityDerivativeMember_30ad2ef3-cf49-4498-9fcb-2a1fd82fb0c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_7de9a1b8-e3ae-4341-a321-955c51f0954c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_67c6639a-139a-41a9-82a5-ae4edd8b3be0" xlink:to="loc_us-gaap_HedgingDesignationAxis_7de9a1b8-e3ae-4341-a321-955c51f0954c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_7de9a1b8-e3ae-4341-a321-955c51f0954c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_7de9a1b8-e3ae-4341-a321-955c51f0954c" xlink:to="loc_us-gaap_HedgingDesignationDomain_7de9a1b8-e3ae-4341-a321-955c51f0954c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_a85ab072-0118-48fa-bdf6-0045ac77f6f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_7de9a1b8-e3ae-4341-a321-955c51f0954c" xlink:to="loc_us-gaap_HedgingDesignationDomain_a85ab072-0118-48fa-bdf6-0045ac77f6f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_9703709c-1053-408d-95bd-e0253a618528" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_a85ab072-0118-48fa-bdf6-0045ac77f6f5" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_9703709c-1053-408d-95bd-e0253a618528" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_b9112c14-0ae5-4273-a3d4-da579d984250" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_67c6639a-139a-41a9-82a5-ae4edd8b3be0" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_b9112c14-0ae5-4273-a3d4-da579d984250" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_b9112c14-0ae5-4273-a3d4-da579d984250_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_b9112c14-0ae5-4273-a3d4-da579d984250" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_b9112c14-0ae5-4273-a3d4-da579d984250_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_cb5207c1-31a0-4622-bdcd-c96d18c7db6a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_b9112c14-0ae5-4273-a3d4-da579d984250" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_cb5207c1-31a0-4622-bdcd-c96d18c7db6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_d638bd63-e4eb-4dde-8936-a830757e6ee7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_cb5207c1-31a0-4622-bdcd-c96d18c7db6a" xlink:to="loc_us-gaap_InterestExpenseMember_d638bd63-e4eb-4dde-8936-a830757e6ee7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_8a96783d-8923-4514-a902-0ce9ff30b3f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_cb5207c1-31a0-4622-bdcd-c96d18c7db6a" xlink:to="loc_us-gaap_CostOfSalesMember_8a96783d-8923-4514-a902-0ce9ff30b3f3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails" xlink:type="extended" id="idbb3963c63ed484fa4adfd941c80dafd_RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_8d12ea01-d6c2-45db-9eba-b01b52d4b87e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_2d860219-62e6-462d-a5e7-a1c0b29a3345" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_8d12ea01-d6c2-45db-9eba-b01b52d4b87e" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_2d860219-62e6-462d-a5e7-a1c0b29a3345" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilities_1635d6e7-27e1-40b0-9c9e-9ecec6e3bb4f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_8d12ea01-d6c2-45db-9eba-b01b52d4b87e" xlink:to="loc_us-gaap_RegulatoryLiabilities_1635d6e7-27e1-40b0-9c9e-9ecec6e3bb4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssets_b96358b3-5e4c-41df-a754-5ea999bb62b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_8d12ea01-d6c2-45db-9eba-b01b52d4b87e" xlink:to="loc_us-gaap_RegulatoryAssets_b96358b3-5e4c-41df-a754-5ea999bb62b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_13efc5ba-c26a-416f-b367-48fdef194b8d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_8d12ea01-d6c2-45db-9eba-b01b52d4b87e" xlink:to="loc_us-gaap_DerivativeTable_13efc5ba-c26a-416f-b367-48fdef194b8d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_959aaaca-d0d3-4947-a376-57af673a88fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_13efc5ba-c26a-416f-b367-48fdef194b8d" xlink:to="loc_us-gaap_HedgingDesignationAxis_959aaaca-d0d3-4947-a376-57af673a88fe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_959aaaca-d0d3-4947-a376-57af673a88fe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_959aaaca-d0d3-4947-a376-57af673a88fe" xlink:to="loc_us-gaap_HedgingDesignationDomain_959aaaca-d0d3-4947-a376-57af673a88fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_cf7713fc-27d2-4f8e-92a5-f1bc66cff39f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_959aaaca-d0d3-4947-a376-57af673a88fe" xlink:to="loc_us-gaap_HedgingDesignationDomain_cf7713fc-27d2-4f8e-92a5-f1bc66cff39f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_4fc5aa5d-342a-4e49-8088-cad03992ce92" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_cf7713fc-27d2-4f8e-92a5-f1bc66cff39f" xlink:to="loc_us-gaap_NondesignatedMember_4fc5aa5d-342a-4e49-8088-cad03992ce92" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_982e67c9-9326-462d-b6a9-2f0b22cdd9c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_13efc5ba-c26a-416f-b367-48fdef194b8d" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_982e67c9-9326-462d-b6a9-2f0b22cdd9c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_982e67c9-9326-462d-b6a9-2f0b22cdd9c0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_982e67c9-9326-462d-b6a9-2f0b22cdd9c0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_982e67c9-9326-462d-b6a9-2f0b22cdd9c0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_2ebc0b29-c644-45db-912d-17383221e681" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_982e67c9-9326-462d-b6a9-2f0b22cdd9c0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_2ebc0b29-c644-45db-912d-17383221e681" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_199003ed-c120-4f05-902d-aa4ab67d5a13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_2ebc0b29-c644-45db-912d-17383221e681" xlink:to="loc_us-gaap_CostOfSalesMember_199003ed-c120-4f05-902d-aa4ab67d5a13" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyAxis_502d10a2-2dab-4763-93ce-c6e7eb1df17d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EnergyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_13efc5ba-c26a-416f-b367-48fdef194b8d" xlink:to="loc_srt_EnergyAxis_502d10a2-2dab-4763-93ce-c6e7eb1df17d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_502d10a2-2dab-4763-93ce-c6e7eb1df17d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_EnergyAxis_502d10a2-2dab-4763-93ce-c6e7eb1df17d" xlink:to="loc_srt_EnergyDomain_502d10a2-2dab-4763-93ce-c6e7eb1df17d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_e42f461e-9e90-4b51-ba9e-dec4a646508f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_EnergyAxis_502d10a2-2dab-4763-93ce-c6e7eb1df17d" xlink:to="loc_srt_EnergyDomain_e42f461e-9e90-4b51-ba9e-dec4a646508f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ElectricityMember_262ee294-92b2-4ca8-9f28-84f13eb084b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ElectricityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_e42f461e-9e90-4b51-ba9e-dec4a646508f" xlink:to="loc_us-gaap_ElectricityMember_262ee294-92b2-4ca8-9f28-84f13eb084b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NaturalGasDistributionMember_ac598f51-8451-4b65-ac50-92940195f159" xlink:href="bkh-20210930.xsd#bkh_NaturalGasDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_e42f461e-9e90-4b51-ba9e-dec4a646508f" xlink:to="loc_bkh_NaturalGasDistributionMember_ac598f51-8451-4b65-ac50-92940195f159" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAxis_d7966dc6-bd54-405e-b898-08a3d3e166e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_13efc5ba-c26a-416f-b367-48fdef194b8d" xlink:to="loc_us-gaap_RegulatoryAssetAxis_d7966dc6-bd54-405e-b898-08a3d3e166e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_d7966dc6-bd54-405e-b898-08a3d3e166e0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAssetAxis_d7966dc6-bd54-405e-b898-08a3d3e166e0" xlink:to="loc_us-gaap_RegulatoryAssetDomain_d7966dc6-bd54-405e-b898-08a3d3e166e0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_71439908-1d29-4e22-84aa-7bb3a04e2218" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAssetAxis_d7966dc6-bd54-405e-b898-08a3d3e166e0" xlink:to="loc_us-gaap_RegulatoryAssetDomain_71439908-1d29-4e22-84aa-7bb3a04e2218" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PriceRiskDerivativeMember_f6394360-304a-4745-8163-1267b294277d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PriceRiskDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_71439908-1d29-4e22-84aa-7bb3a04e2218" xlink:to="loc_us-gaap_PriceRiskDerivativeMember_f6394360-304a-4745-8163-1267b294277d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityAxis_9fabf215-09c4-48ed-8256-463cf79e8f52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_13efc5ba-c26a-416f-b367-48fdef194b8d" xlink:to="loc_us-gaap_RegulatoryLiabilityAxis_9fabf215-09c4-48ed-8256-463cf79e8f52" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_9fabf215-09c4-48ed-8256-463cf79e8f52_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_9fabf215-09c4-48ed-8256-463cf79e8f52" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_9fabf215-09c4-48ed-8256-463cf79e8f52_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_05970351-ddc5-41f3-8bb8-228bd0db0b44" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_9fabf215-09c4-48ed-8256-463cf79e8f52" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_05970351-ddc5-41f3-8bb8-228bd0db0b44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PriceRiskDerivativeMember_8891132c-c129-465e-bae8-82efd19ec835" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PriceRiskDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_05970351-ddc5-41f3-8bb8-228bd0db0b44" xlink:to="loc_us-gaap_PriceRiskDerivativeMember_8891132c-c129-465e-bae8-82efd19ec835" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FairValueMeasurementsScheduleofFairValuesDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FairValueMeasurementsScheduleofFairValuesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FairValueMeasurementsScheduleofFairValuesDetails" xlink:type="extended" id="ic6a93cdbd3004e0ea93243a897d132d7_FairValueMeasurementsScheduleofFairValuesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_ea26ab4a-9de4-40be-9b62-04c06428f074" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_DerivativeAssets_ea26ab4a-9de4-40be-9b62-04c06428f074" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset_ef4797f2-0706-485f-b3c5-93fbcff8b4e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset_ef4797f2-0706-485f-b3c5-93fbcff8b4e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_12c9895d-c116-4444-a3b1-ea3a15fa9d2e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_12c9895d-c116-4444-a3b1-ea3a15fa9d2e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_9ab1afd0-520a-47f4-bd25-f1fc403398e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_DerivativeLiabilities_9ab1afd0-520a-47f4-bd25-f1fc403398e7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset_2bf79ebd-87ba-497c-85f5-45239e0b4dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset_2bf79ebd-87ba-497c-85f5-45239e0b4dfb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_947af30c-1de2-4577-9153-46b544569ba3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_947af30c-1de2-4577-9153-46b544569ba3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_44eb4740-7576-4e22-ba80-f145c4da4696" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_44eb4740-7576-4e22-ba80-f145c4da4696" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_d5a3716e-82d7-4057-a16d-c140b30dc71f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_d5a3716e-82d7-4057-a16d-c140b30dc71f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4a7edc1a-f01d-4853-9f9c-3cf01747e859" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_0a932b80-77a5-48d8-91a6-f0dd2f63c908" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4a7edc1a-f01d-4853-9f9c-3cf01747e859" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_d8408e86-c4a5-444b-b2f8-704f437b7c6c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4a7edc1a-f01d-4853-9f9c-3cf01747e859" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_d8408e86-c4a5-444b-b2f8-704f437b7c6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_d8408e86-c4a5-444b-b2f8-704f437b7c6c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_d8408e86-c4a5-444b-b2f8-704f437b7c6c" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_d8408e86-c4a5-444b-b2f8-704f437b7c6c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_6a0b4f73-33ba-4223-9404-41961b67b591" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_d8408e86-c4a5-444b-b2f8-704f437b7c6c" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_6a0b4f73-33ba-4223-9404-41961b67b591" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_71859561-844f-42e3-bfc7-8c907fd3531a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_6a0b4f73-33ba-4223-9404-41961b67b591" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_71859561-844f-42e3-bfc7-8c907fd3531a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_3325b2e0-4789-42b0-bd6d-4a3680db2162" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4a7edc1a-f01d-4853-9f9c-3cf01747e859" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_3325b2e0-4789-42b0-bd6d-4a3680db2162" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3325b2e0-4789-42b0-bd6d-4a3680db2162_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3325b2e0-4789-42b0-bd6d-4a3680db2162" xlink:to="loc_us-gaap_SegmentDomain_3325b2e0-4789-42b0-bd6d-4a3680db2162_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_698ce90e-fc3f-4a07-b7e3-b59fb6b7dff3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3325b2e0-4789-42b0-bd6d-4a3680db2162" xlink:to="loc_us-gaap_SegmentDomain_698ce90e-fc3f-4a07-b7e3-b59fb6b7dff3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_37fab462-3eb6-41c3-9023-28991c11ed93" xlink:href="bkh-20210930.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_698ce90e-fc3f-4a07-b7e3-b59fb6b7dff3" xlink:to="loc_bkh_GasUtilitiesMember_37fab462-3eb6-41c3-9023-28991c11ed93" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_c42def1d-10d3-4d27-9b00-eed16a58e1b0" xlink:href="bkh-20210930.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_698ce90e-fc3f-4a07-b7e3-b59fb6b7dff3" xlink:to="loc_bkh_ElectricUtilitiesMember_c42def1d-10d3-4d27-9b00-eed16a58e1b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b57fc46b-0164-4ae7-af6c-4a3167d671d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4a7edc1a-f01d-4853-9f9c-3cf01747e859" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b57fc46b-0164-4ae7-af6c-4a3167d671d4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b57fc46b-0164-4ae7-af6c-4a3167d671d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b57fc46b-0164-4ae7-af6c-4a3167d671d4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_b57fc46b-0164-4ae7-af6c-4a3167d671d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c791fc1e-a2f0-49fd-9d30-ca7a9b977efa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_b57fc46b-0164-4ae7-af6c-4a3167d671d4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c791fc1e-a2f0-49fd-9d30-ca7a9b977efa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_d4a8f133-5faa-40cf-9b95-80262aec8cba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c791fc1e-a2f0-49fd-9d30-ca7a9b977efa" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_d4a8f133-5faa-40cf-9b95-80262aec8cba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_84f78674-4a1e-499a-8022-cfd917bf900d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c791fc1e-a2f0-49fd-9d30-ca7a9b977efa" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_84f78674-4a1e-499a-8022-cfd917bf900d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_3ec72dd4-b37b-4724-8aa0-880fc8555c7d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c791fc1e-a2f0-49fd-9d30-ca7a9b977efa" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_3ec72dd4-b37b-4724-8aa0-880fc8555c7d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_f218351f-3356-4f9c-b900-7f91b760763c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4a7edc1a-f01d-4853-9f9c-3cf01747e859" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_f218351f-3356-4f9c-b900-7f91b760763c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f218351f-3356-4f9c-b900-7f91b760763c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_f218351f-3356-4f9c-b900-7f91b760763c" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f218351f-3356-4f9c-b900-7f91b760763c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_e8790e07-e8f2-4b31-8904-6ccb931ca2b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_f218351f-3356-4f9c-b900-7f91b760763c" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_e8790e07-e8f2-4b31-8904-6ccb931ca2b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9b97370a-e636-429b-bc29-40570bc40584" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_e8790e07-e8f2-4b31-8904-6ccb931ca2b5" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9b97370a-e636-429b-bc29-40570bc40584" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_dac9d588-4c00-4ccb-86b0-c56daa628da9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9b97370a-e636-429b-bc29-40570bc40584" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_dac9d588-4c00-4ccb-86b0-c56daa628da9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NettingContractCategoryAxis_e7fbab96-37a3-476f-b3a4-7066858c1fee" xlink:href="bkh-20210930.xsd#bkh_NettingContractCategoryAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4a7edc1a-f01d-4853-9f9c-3cf01747e859" xlink:to="loc_bkh_NettingContractCategoryAxis_e7fbab96-37a3-476f-b3a4-7066858c1fee" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NettingContractCategoryDomain_e7fbab96-37a3-476f-b3a4-7066858c1fee_default" xlink:href="bkh-20210930.xsd#bkh_NettingContractCategoryDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_bkh_NettingContractCategoryAxis_e7fbab96-37a3-476f-b3a4-7066858c1fee" xlink:to="loc_bkh_NettingContractCategoryDomain_e7fbab96-37a3-476f-b3a4-7066858c1fee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NettingContractCategoryDomain_2ddb7c9f-c4fe-4c6d-a715-2d99a5811eed" xlink:href="bkh-20210930.xsd#bkh_NettingContractCategoryDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_bkh_NettingContractCategoryAxis_e7fbab96-37a3-476f-b3a4-7066858c1fee" xlink:to="loc_bkh_NettingContractCategoryDomain_2ddb7c9f-c4fe-4c6d-a715-2d99a5811eed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ContractSubjecttoMasterNettingMember_58526a2d-50cd-47d7-968a-fc88b64c1d6f" xlink:href="bkh-20210930.xsd#bkh_ContractSubjecttoMasterNettingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_NettingContractCategoryDomain_2ddb7c9f-c4fe-4c6d-a715-2d99a5811eed" xlink:to="loc_bkh_ContractSubjecttoMasterNettingMember_58526a2d-50cd-47d7-968a-fc88b64c1d6f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FairValueMeasurementsOtherFairValueMeasurementsDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#FairValueMeasurementsOtherFairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FairValueMeasurementsOtherFairValueMeasurementsDetails" xlink:type="extended" id="ia273faaa816e4c9eb380e552c86c2ac2_FairValueMeasurementsOtherFairValueMeasurementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_23a2eac6-324b-4ba8-915c-cbdf193e8b48" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_f19f51cf-2632-4050-9b39-1578f5a80198" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_23a2eac6-324b-4ba8-915c-cbdf193e8b48" xlink:to="loc_us-gaap_LongTermDebt_f19f51cf-2632-4050-9b39-1578f5a80198" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_af1bc57e-3399-4547-8f04-a859dc5821b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_23a2eac6-324b-4ba8-915c-cbdf193e8b48" xlink:to="loc_us-gaap_LongTermDebtFairValue_af1bc57e-3399-4547-8f04-a859dc5821b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_280ff4dc-034e-4448-bcdb-82c2c3c1d385" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_23a2eac6-324b-4ba8-915c-cbdf193e8b48" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_280ff4dc-034e-4448-bcdb-82c2c3c1d385" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_cff94915-a2ed-45a7-92d8-67e750ff6281" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_280ff4dc-034e-4448-bcdb-82c2c3c1d385" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_cff94915-a2ed-45a7-92d8-67e750ff6281" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_cff94915-a2ed-45a7-92d8-67e750ff6281_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_cff94915-a2ed-45a7-92d8-67e750ff6281" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_cff94915-a2ed-45a7-92d8-67e750ff6281_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_306f9991-8c48-4339-8b19-99bc658884b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_cff94915-a2ed-45a7-92d8-67e750ff6281" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_306f9991-8c48-4339-8b19-99bc658884b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9de186a9-6597-4588-a157-066d87a64650" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_306f9991-8c48-4339-8b19-99bc658884b5" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9de186a9-6597-4588-a157-066d87a64650" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_7b86c3d4-e05b-4475-b9d8-14bb26d0e3d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9de186a9-6597-4588-a157-066d87a64650" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_7b86c3d4-e05b-4475-b9d8-14bb26d0e3d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_2af8783e-c4f0-46bb-89e6-629541d32e24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_9de186a9-6597-4588-a157-066d87a64650" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_2af8783e-c4f0-46bb-89e6-629541d32e24" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="extended" id="i55e3b7ed017f498b9a2615a9422c6164_OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedStatementOfIncomeCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsIncurred_47525d7b-f374-4da6-82f7-390c4d234d4e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestCostsIncurred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:to="loc_us-gaap_InterestCostsIncurred_47525d7b-f374-4da6-82f7-390c4d234d4e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelPurchasedPowerAndCostOfGasSold_b974effb-e2c7-4d43-9d0c-8e79f1d046e0" xlink:href="bkh-20210930.xsd#bkh_FuelPurchasedPowerAndCostOfGasSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:to="loc_bkh_FuelPurchasedPowerAndCostOfGasSold_b974effb-e2c7-4d43-9d0c-8e79f1d046e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OperatingExpenseMaintenanceOperationsandOtherCostsandExpense_88f7c84e-ad50-466e-ae69-bbc724152d58" xlink:href="bkh-20210930.xsd#bkh_OperatingExpenseMaintenanceOperationsandOtherCostsandExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:to="loc_bkh_OperatingExpenseMaintenanceOperationsandOtherCostsandExpense_88f7c84e-ad50-466e-ae69-bbc724152d58" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_45988674-c9e1-45a8-ae18-01478e19cbce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_45988674-c9e1-45a8-ae18-01478e19cbce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_fa05eac2-d85d-4b80-a051-72881bf72c53" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_fa05eac2-d85d-4b80-a051-72881bf72c53" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_ef41b941-0e44-4700-8019-d4755fcd6cc0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:to="loc_us-gaap_ProfitLoss_ef41b941-0e44-4700-8019-d4755fcd6cc0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedStatementOfComprehensiveIncomeTable_d1255af9-2e27-42f2-a60a-0d38f8f89634" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CondensedStatementOfComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_8e44a6e2-49ca-451c-b2c1-e3fa2eaa7d2a" xlink:to="loc_srt_CondensedStatementOfComprehensiveIncomeTable_d1255af9-2e27-42f2-a60a-0d38f8f89634" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_b3a0bdba-a33f-4ac9-aca9-171ab8c0aa02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedStatementOfComprehensiveIncomeTable_d1255af9-2e27-42f2-a60a-0d38f8f89634" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_b3a0bdba-a33f-4ac9-aca9-171ab8c0aa02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_b3a0bdba-a33f-4ac9-aca9-171ab8c0aa02_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_b3a0bdba-a33f-4ac9-aca9-171ab8c0aa02" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_b3a0bdba-a33f-4ac9-aca9-171ab8c0aa02_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_417db626-56c6-4a72-8562-e5297583c74b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_b3a0bdba-a33f-4ac9-aca9-171ab8c0aa02" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_417db626-56c6-4a72-8562-e5297583c74b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_20597315-ed09-4fc6-8df3-4064ff044d50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_417db626-56c6-4a72-8562-e5297583c74b" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_20597315-ed09-4fc6-8df3-4064ff044d50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_5d1b47eb-b2f0-4428-aa2e-ec861403dbb2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedStatementOfComprehensiveIncomeTable_d1255af9-2e27-42f2-a60a-0d38f8f89634" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_5d1b47eb-b2f0-4428-aa2e-ec861403dbb2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_5d1b47eb-b2f0-4428-aa2e-ec861403dbb2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_5d1b47eb-b2f0-4428-aa2e-ec861403dbb2" xlink:to="loc_us-gaap_EquityComponentDomain_5d1b47eb-b2f0-4428-aa2e-ec861403dbb2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_fec24587-1035-42d4-8f0c-4f007cc5c76c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_5d1b47eb-b2f0-4428-aa2e-ec861403dbb2" xlink:to="loc_us-gaap_EquityComponentDomain_fec24587-1035-42d4-8f0c-4f007cc5c76c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_0c959ae8-44bc-454c-acd0-5df2db60554e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_fec24587-1035-42d4-8f0c-4f007cc5c76c" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_0c959ae8-44bc-454c-acd0-5df2db60554e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_c10e845b-752c-4ee8-a057-5d1109918eb8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_fec24587-1035-42d4-8f0c-4f007cc5c76c" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_c10e845b-752c-4ee8-a057-5d1109918eb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_7972d5f8-8485-4459-a597-da26425e2631" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_fec24587-1035-42d4-8f0c-4f007cc5c76c" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_7972d5f8-8485-4459-a597-da26425e2631" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_3545f4ec-2c9c-44e9-89d8-12d421099c09" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_fec24587-1035-42d4-8f0c-4f007cc5c76c" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_3545f4ec-2c9c-44e9-89d8-12d421099c09" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_e72b9a92-97b7-40fe-8396-dd1dfaf0cd89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedStatementOfComprehensiveIncomeTable_d1255af9-2e27-42f2-a60a-0d38f8f89634" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_e72b9a92-97b7-40fe-8396-dd1dfaf0cd89" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_e72b9a92-97b7-40fe-8396-dd1dfaf0cd89_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_e72b9a92-97b7-40fe-8396-dd1dfaf0cd89" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_e72b9a92-97b7-40fe-8396-dd1dfaf0cd89_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_9ef725a2-36bb-45e8-8db3-8ae55690ae55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_e72b9a92-97b7-40fe-8396-dd1dfaf0cd89" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_9ef725a2-36bb-45e8-8db3-8ae55690ae55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_ddce1948-2897-499c-aac7-99218374b81b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_9ef725a2-36bb-45e8-8db3-8ae55690ae55" xlink:to="loc_us-gaap_InterestRateSwapMember_ddce1948-2897-499c-aac7-99218374b81b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_f0f13534-984b-40b2-ab8e-c150d3aa3443" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_9ef725a2-36bb-45e8-8db3-8ae55690ae55" xlink:to="loc_us-gaap_CommodityContractMember_f0f13534-984b-40b2-ab8e-c150d3aa3443" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeAccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#OtherComprehensiveIncomeAccumulatedOtherComprehensiveIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeAccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended" id="i89bf3f7df35e42068b6e1eddba974d4f_OtherComprehensiveIncomeAccumulatedOtherComprehensiveIncomeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_325738ea-e720-4095-b1e4-dc0e436aa7ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_6f27777e-29ab-473c-9cde-d38f749c35ef" xlink:href="bkh-20210930.xsd#bkh_AccumulatedOtherComprehensiveIncomeRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_325738ea-e720-4095-b1e4-dc0e436aa7ab" xlink:to="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_6f27777e-29ab-473c-9cde-d38f749c35ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_e8aa22d7-2fd7-4dad-8e72-7660ef250769" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_6f27777e-29ab-473c-9cde-d38f749c35ef" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_e8aa22d7-2fd7-4dad-8e72-7660ef250769" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_f400bbd5-0714-4953-9880-6f1da8b8a69d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_6f27777e-29ab-473c-9cde-d38f749c35ef" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_f400bbd5-0714-4953-9880-6f1da8b8a69d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_ed855dde-ebc3-4eb9-820b-0f3e7b66f004" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_6f27777e-29ab-473c-9cde-d38f749c35ef" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_ed855dde-ebc3-4eb9-820b-0f3e7b66f004" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_7ad3bb7c-1eac-4c0d-9515-ee8c3b27005b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_a61b715f-30f6-4645-8c18-2728fe751360" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_325738ea-e720-4095-b1e4-dc0e436aa7ab" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_a61b715f-30f6-4645-8c18-2728fe751360" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_d4d732ed-3a3b-483c-a835-9bddc1f97e58" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_a61b715f-30f6-4645-8c18-2728fe751360" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_d4d732ed-3a3b-483c-a835-9bddc1f97e58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_d4d732ed-3a3b-483c-a835-9bddc1f97e58_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_d4d732ed-3a3b-483c-a835-9bddc1f97e58" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_d4d732ed-3a3b-483c-a835-9bddc1f97e58_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_54cc09f2-ff63-4c57-980e-f687a6dee5bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_d4d732ed-3a3b-483c-a835-9bddc1f97e58" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_54cc09f2-ff63-4c57-980e-f687a6dee5bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_da28b76e-0879-412e-82c6-3cbb678267f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_54cc09f2-ff63-4c57-980e-f687a6dee5bb" xlink:to="loc_us-gaap_InterestRateSwapMember_da28b76e-0879-412e-82c6-3cbb678267f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_dd84dd51-13dd-4a76-98b9-2cd99d22c7b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_54cc09f2-ff63-4c57-980e-f687a6dee5bb" xlink:to="loc_us-gaap_CommodityContractMember_dd84dd51-13dd-4a76-98b9-2cd99d22c7b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_70edde35-bbd1-459a-8083-e43976e5293e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_a61b715f-30f6-4645-8c18-2728fe751360" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_70edde35-bbd1-459a-8083-e43976e5293e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_70edde35-bbd1-459a-8083-e43976e5293e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_70edde35-bbd1-459a-8083-e43976e5293e" xlink:to="loc_us-gaap_EquityComponentDomain_70edde35-bbd1-459a-8083-e43976e5293e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c26446e3-fb8c-4215-922c-7b121a9b4620" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_70edde35-bbd1-459a-8083-e43976e5293e" xlink:to="loc_us-gaap_EquityComponentDomain_c26446e3-fb8c-4215-922c-7b121a9b4620" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_4ca5b297-afb4-42e9-9150-23941b6a3459" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c26446e3-fb8c-4215-922c-7b121a9b4620" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_4ca5b297-afb4-42e9-9150-23941b6a3459" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_302fe5eb-38e9-4b2b-9bf4-3a7ff910e76c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c26446e3-fb8c-4215-922c-7b121a9b4620" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_302fe5eb-38e9-4b2b-9bf4-3a7ff910e76c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_641c308f-c3cb-4ae7-bf26-52c71b8701a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c26446e3-fb8c-4215-922c-7b121a9b4620" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_641c308f-c3cb-4ae7-bf26-52c71b8701a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_c341a42d-fc22-4735-a9ab-f2e7cb00f7bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_a61b715f-30f6-4645-8c18-2728fe751360" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_c341a42d-fc22-4735-a9ab-f2e7cb00f7bb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_c341a42d-fc22-4735-a9ab-f2e7cb00f7bb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_c341a42d-fc22-4735-a9ab-f2e7cb00f7bb" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_c341a42d-fc22-4735-a9ab-f2e7cb00f7bb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_400c6946-cc08-4767-a1ea-95211d912dce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_c341a42d-fc22-4735-a9ab-f2e7cb00f7bb" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_400c6946-cc08-4767-a1ea-95211d912dce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_d10a6d24-490c-48bf-8c37-3c6216c32cc1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_400c6946-cc08-4767-a1ea-95211d912dce" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_d10a6d24-490c-48bf-8c37-3c6216c32cc1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EmployeeBenefitPlansDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#EmployeeBenefitPlansDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EmployeeBenefitPlansDetails" xlink:type="extended" id="i1e4d4572f8fe4168949a0e61b5a424a7_EmployeeBenefitPlansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_48c88da0-c48b-4809-82aa-3fd0829804b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_48c88da0-c48b-4809-82aa-3fd0829804b7" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_8d45beec-079f-47b5-b612-9154bab0719b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_8d45beec-079f-47b5-b612-9154bab0719b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_4f59064a-2127-4ad8-b04d-73b3177ea3d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_4f59064a-2127-4ad8-b04d-73b3177ea3d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_58cbcd0b-6de8-43d8-adf2-b7ff8337bc75" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_58cbcd0b-6de8-43d8-adf2-b7ff8337bc75" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_e4624f1c-ca8e-4837-b211-1160f0f0fd74" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_e4624f1c-ca8e-4837-b211-1160f0f0fd74" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_7e96ca0b-84f8-416d-b59a-4dada4001e92" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_7e96ca0b-84f8-416d-b59a-4dada4001e92" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_32c0171b-c2d7-4081-b5a8-9ae715909016" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_daea9511-a5fe-4340-9464-c94f0f521d51" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_32c0171b-c2d7-4081-b5a8-9ae715909016" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_1d412c50-46a8-4a87-8111-67e259e9034c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_48c88da0-c48b-4809-82aa-3fd0829804b7" xlink:to="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_1d412c50-46a8-4a87-8111-67e259e9034c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_1965d84f-9764-493c-8cf1-8d4feced110c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_1d412c50-46a8-4a87-8111-67e259e9034c" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_1965d84f-9764-493c-8cf1-8d4feced110c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_66f22197-d6a3-44a0-b3f9-bc774edcd85c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_1d412c50-46a8-4a87-8111-67e259e9034c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_66f22197-d6a3-44a0-b3f9-bc774edcd85c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_ab39abb7-5d04-4281-ae83-0c14d5fc11a2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_1d412c50-46a8-4a87-8111-67e259e9034c" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_ab39abb7-5d04-4281-ae83-0c14d5fc11a2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_a14ed7f5-9f70-41c3-909d-e6a1951039e5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_48c88da0-c48b-4809-82aa-3fd0829804b7" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_a14ed7f5-9f70-41c3-909d-e6a1951039e5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_b290de40-da9e-4077-b2de-47efd057909d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_a14ed7f5-9f70-41c3-909d-e6a1951039e5" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_b290de40-da9e-4077-b2de-47efd057909d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_b290de40-da9e-4077-b2de-47efd057909d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_b290de40-da9e-4077-b2de-47efd057909d" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_b290de40-da9e-4077-b2de-47efd057909d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_0789bee7-89ac-4ed3-b603-226aacb6eba9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_b290de40-da9e-4077-b2de-47efd057909d" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_0789bee7-89ac-4ed3-b603-226aacb6eba9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_73e9e684-c45f-4c49-b130-2832b5c61541" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_0789bee7-89ac-4ed3-b603-226aacb6eba9" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_73e9e684-c45f-4c49-b130-2832b5c61541" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_95762bd8-0000-4e30-a44d-77130682e359" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_0789bee7-89ac-4ed3-b603-226aacb6eba9" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_95762bd8-0000-4e30-a44d-77130682e359" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_28140fec-01f9-47e1-8a23-78877fe9e2cd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_0789bee7-89ac-4ed3-b603-226aacb6eba9" xlink:to="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_28140fec-01f9-47e1-8a23-78877fe9e2cd" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/IncomeTaxesWinterStormUriDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#IncomeTaxesWinterStormUriDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/IncomeTaxesWinterStormUriDetails" xlink:type="extended" id="i9048690ccf55499fba52d12b651aeb45_IncomeTaxesWinterStormUriDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_39d88e6d-aad4-42b1-9d52-9866f05673eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_a7924b22-47df-431e-88ea-0b16696fad0c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_39d88e6d-aad4-42b1-9d52-9866f05673eb" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_a7924b22-47df-431e-88ea-0b16696fad0c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c23d2956-a885-4be5-ba69-b5c3eda414c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_39d88e6d-aad4-42b1-9d52-9866f05673eb" xlink:to="loc_us-gaap_StatementTable_c23d2956-a885-4be5-ba69-b5c3eda414c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemAxis_e005d1ca-f782-4701-aa34-8ac1ddea3fbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c23d2956-a885-4be5-ba69-b5c3eda414c4" xlink:to="loc_us-gaap_UnusualOrInfrequentItemAxis_e005d1ca-f782-4701-aa34-8ac1ddea3fbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_e005d1ca-f782-4701-aa34-8ac1ddea3fbd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_e005d1ca-f782-4701-aa34-8ac1ddea3fbd" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_e005d1ca-f782-4701-aa34-8ac1ddea3fbd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_eba4e3b8-5bd7-4e9c-bfd1-847ee55dcbdc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_e005d1ca-f782-4701-aa34-8ac1ddea3fbd" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_eba4e3b8-5bd7-4e9c-bfd1-847ee55dcbdc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WinterStormUriMember_8120fff2-ff95-438f-9d16-65acdf5dc855" xlink:href="bkh-20210930.xsd#bkh_WinterStormUriMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_eba4e3b8-5bd7-4e9c-bfd1-847ee55dcbdc" xlink:to="loc_bkh_WinterStormUriMember_8120fff2-ff95-438f-9d16-65acdf5dc855" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/IncomeTaxesDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#IncomeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/IncomeTaxesDetails" xlink:type="extended" id="i41c90f1959f7485ea9ee7333a092e458_IncomeTaxesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_4d0c1599-8fba-4dcc-a1cf-b96b70c961e4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_4d0c1599-8fba-4dcc-a1cf-b96b70c961e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_b5a1a393-01fb-454e-994c-dee8aed4cd31" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_b5a1a393-01fb-454e-994c-dee8aed4cd31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017AmountTaxBenefitFromBillCredit_443326b8-8e2d-4393-a284-c60fc72a8e9b" xlink:href="bkh-20210930.xsd#bkh_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017AmountTaxBenefitFromBillCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_bkh_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017AmountTaxBenefitFromBillCredit_443326b8-8e2d-4393-a284-c60fc72a8e9b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities_b5e1e5a3-ab4d-41e8-8802-b743e539f56b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities_b5e1e5a3-ab4d-41e8-8802-b743e539f56b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_EffectiveIncomeTaxReconciliationTaxBenefitFromAmortizationOfExcessDeferredIncomeTaxes_f77b1553-86a2-4402-8d3e-7ee00d790e1b" xlink:href="bkh-20210930.xsd#bkh_EffectiveIncomeTaxReconciliationTaxBenefitFromAmortizationOfExcessDeferredIncomeTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_bkh_EffectiveIncomeTaxReconciliationTaxBenefitFromAmortizationOfExcessDeferredIncomeTaxes_f77b1553-86a2-4402-8d3e-7ee00d790e1b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationOtherAdjustments_6a90a220-35d8-4a35-9703-e7f11998a5d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxReconciliationOtherAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_us-gaap_IncomeTaxReconciliationOtherAdjustments_6a90a220-35d8-4a35-9703-e7f11998a5d1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_EffectiveIncomeTaxReconciliationTaxFlowThroughBenefitFromRepairsAndIndirectCosts_b09d44b0-95e0-46c3-b976-c7d71252f4d5" xlink:href="bkh-20210930.xsd#bkh_EffectiveIncomeTaxReconciliationTaxFlowThroughBenefitFromRepairsAndIndirectCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_bkh_EffectiveIncomeTaxReconciliationTaxFlowThroughBenefitFromRepairsAndIndirectCosts_b09d44b0-95e0-46c3-b976-c7d71252f4d5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_b25588a8-8eea-4e0b-8e29-e1fb4b4b2c77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_1d397ed9-6019-48ad-9cca-5cc64306cd38" xlink:to="loc_us-gaap_StatementTable_b25588a8-8eea-4e0b-8e29-e1fb4b4b2c77" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_eaedef0e-1e81-42a0-9dec-185911ce9c98" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b25588a8-8eea-4e0b-8e29-e1fb4b4b2c77" xlink:to="loc_dei_LegalEntityAxis_eaedef0e-1e81-42a0-9dec-185911ce9c98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_eaedef0e-1e81-42a0-9dec-185911ce9c98_default" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_eaedef0e-1e81-42a0-9dec-185911ce9c98" xlink:to="loc_dei_EntityDomain_eaedef0e-1e81-42a0-9dec-185911ce9c98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_43547a22-9268-492f-b371-49148f3dae04" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_eaedef0e-1e81-42a0-9dec-185911ce9c98" xlink:to="loc_dei_EntityDomain_43547a22-9268-492f-b371-49148f3dae04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ColoradoElectricAndNebraskaGasMember_4e6d1da2-2409-4960-9810-8b4c56035a0d" xlink:href="bkh-20210930.xsd#bkh_ColoradoElectricAndNebraskaGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_43547a22-9268-492f-b371-49148f3dae04" xlink:to="loc_bkh_ColoradoElectricAndNebraskaGasMember_4e6d1da2-2409-4960-9810-8b4c56035a0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilityAxis_df713d36-bfe1-4f97-9aa4-23a63e1562ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PublicUtilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b25588a8-8eea-4e0b-8e29-e1fb4b4b2c77" xlink:to="loc_us-gaap_PublicUtilityAxis_df713d36-bfe1-4f97-9aa4-23a63e1562ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilityPlantDomain_df713d36-bfe1-4f97-9aa4-23a63e1562ef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UtilityPlantDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilityAxis_df713d36-bfe1-4f97-9aa4-23a63e1562ef" xlink:to="loc_us-gaap_UtilityPlantDomain_df713d36-bfe1-4f97-9aa4-23a63e1562ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilityPlantDomain_6d5fe0b4-107e-441a-a29d-b8d6f0ffbeb3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UtilityPlantDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilityAxis_df713d36-bfe1-4f97-9aa4-23a63e1562ef" xlink:to="loc_us-gaap_UtilityPlantDomain_6d5fe0b4-107e-441a-a29d-b8d6f0ffbeb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WindAssetsMember_82c8d4ed-1407-4819-a818-43e8cc183345" xlink:href="bkh-20210930.xsd#bkh_WindAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UtilityPlantDomain_6d5fe0b4-107e-441a-a29d-b8d6f0ffbeb3" xlink:to="loc_bkh_WindAssetsMember_82c8d4ed-1407-4819-a818-43e8cc183345" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/BusinessSegmentInformationSegmentandCorporateAssetsDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#BusinessSegmentInformationSegmentandCorporateAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/BusinessSegmentInformationSegmentandCorporateAssetsDetails" xlink:type="extended" id="icf9e183e51de4d1b8cce63975fd8f50c_BusinessSegmentInformationSegmentandCorporateAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_fa62df01-c4b8-4f0f-b105-a6655ced5b43" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingAssetReconcilingItemLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_ac0e14b9-5cd7-440a-8da5-865556d46d49" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_fa62df01-c4b8-4f0f-b105-a6655ced5b43" xlink:to="loc_us-gaap_Assets_ac0e14b9-5cd7-440a-8da5-865556d46d49" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_22a04e39-3bd6-4197-a65b-c19b498bcfe7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_fa62df01-c4b8-4f0f-b105-a6655ced5b43" xlink:to="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_22a04e39-3bd6-4197-a65b-c19b498bcfe7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_1e8a338c-082b-4168-b2aa-6945ecd2c061" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_22a04e39-3bd6-4197-a65b-c19b498bcfe7" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_1e8a338c-082b-4168-b2aa-6945ecd2c061" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1e8a338c-082b-4168-b2aa-6945ecd2c061_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1e8a338c-082b-4168-b2aa-6945ecd2c061" xlink:to="loc_us-gaap_SegmentDomain_1e8a338c-082b-4168-b2aa-6945ecd2c061_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ef426152-2ca0-413a-abe4-f72d7523b880" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1e8a338c-082b-4168-b2aa-6945ecd2c061" xlink:to="loc_us-gaap_SegmentDomain_ef426152-2ca0-413a-abe4-f72d7523b880" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_1e7ddddd-e3d7-4005-981c-19e78f3fc0d1" xlink:href="bkh-20210930.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef426152-2ca0-413a-abe4-f72d7523b880" xlink:to="loc_bkh_ElectricUtilitiesMember_1e7ddddd-e3d7-4005-981c-19e78f3fc0d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_29af9c57-0bda-4ac1-8357-b117c31301b6" xlink:href="bkh-20210930.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef426152-2ca0-413a-abe4-f72d7523b880" xlink:to="loc_bkh_GasUtilitiesMember_29af9c57-0bda-4ac1-8357-b117c31301b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PowerGenerationMember_b8720481-e1e8-40dc-af37-e8a27cce6c14" xlink:href="bkh-20210930.xsd#bkh_PowerGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef426152-2ca0-413a-abe4-f72d7523b880" xlink:to="loc_bkh_PowerGenerationMember_b8720481-e1e8-40dc-af37-e8a27cce6c14" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MiningMember_0b0d9623-c892-43dd-9a42-8b79a8e00fbf" xlink:href="bkh-20210930.xsd#bkh_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef426152-2ca0-413a-abe4-f72d7523b880" xlink:to="loc_bkh_MiningMember_0b0d9623-c892-43dd-9a42-8b79a8e00fbf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_6a93facc-0e25-42f1-b44d-0278349e29eb" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_22a04e39-3bd6-4197-a65b-c19b498bcfe7" xlink:to="loc_srt_ConsolidationItemsAxis_6a93facc-0e25-42f1-b44d-0278349e29eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_6a93facc-0e25-42f1-b44d-0278349e29eb_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_6a93facc-0e25-42f1-b44d-0278349e29eb" xlink:to="loc_srt_ConsolidationItemsDomain_6a93facc-0e25-42f1-b44d-0278349e29eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_056d59c0-c10b-4be6-8861-ea031f850042" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_6a93facc-0e25-42f1-b44d-0278349e29eb" xlink:to="loc_srt_ConsolidationItemsDomain_056d59c0-c10b-4be6-8861-ea031f850042" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_147b2d2d-75a0-436f-b05a-84fbdbc1c219" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_056d59c0-c10b-4be6-8861-ea031f850042" xlink:to="loc_us-gaap_CorporateNonSegmentMember_147b2d2d-75a0-436f-b05a-84fbdbc1c219" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails" xlink:type="simple" xlink:href="bkh-20210930.xsd#BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails" xlink:type="extended" id="i8ebc5cca06f74ceab97337ab57358ba2_BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_3959a7bf-2b75-4e48-961f-2f3e040f79bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_3959a7bf-2b75-4e48-961f-2f3e040f79bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_fb54f6c1-c3ed-4eb2-ae68-c5132786caea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_Revenues_fb54f6c1-c3ed-4eb2-ae68-c5132786caea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_553c217f-fc24-49d4-9ef7-14b3b261823b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_OperatingIncomeLoss_553c217f-fc24-49d4-9ef7-14b3b261823b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_197efafd-2241-4c5c-b42e-72904f8d8e66" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_197efafd-2241-4c5c-b42e-72904f8d8e66" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetImpairmentCharges_8f493aec-e013-40d4-aac9-7951d016c8f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_OtherAssetImpairmentCharges_8f493aec-e013-40d4-aac9-7951d016c8f5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_e2369bb0-e5fb-4fa7-90f1-43f578b384a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_e2369bb0-e5fb-4fa7-90f1-43f578b384a3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_e473ebfd-2a0f-421c-9ec1-c8c0e5b847c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_e473ebfd-2a0f-421c-9ec1-c8c0e5b847c9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_2f01e607-269e-4221-8ca8-2f8410657c00" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_ProfitLoss_2f01e607-269e-4221-8ca8-2f8410657c00" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_868dc7cf-80da-4c61-9485-f10bd36b5922" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_868dc7cf-80da-4c61-9485-f10bd36b5922" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_58e15251-d1ea-4df7-a06b-6e0717fd2355" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_NetIncomeLoss_58e15251-d1ea-4df7-a06b-6e0717fd2355" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7bcde4d3-5137-4ddd-9c23-2d34b5c33a88" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_209de68d-c108-4957-a383-97e8535ea2d1" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7bcde4d3-5137-4ddd-9c23-2d34b5c33a88" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_a5a1dc39-9907-4f5a-9099-69b95ce33605" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7bcde4d3-5137-4ddd-9c23-2d34b5c33a88" xlink:to="loc_srt_MajorCustomersAxis_a5a1dc39-9907-4f5a-9099-69b95ce33605" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_a5a1dc39-9907-4f5a-9099-69b95ce33605_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_a5a1dc39-9907-4f5a-9099-69b95ce33605" xlink:to="loc_srt_NameOfMajorCustomerDomain_a5a1dc39-9907-4f5a-9099-69b95ce33605_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_4964778d-d0d3-47ba-8352-5b2d97d0158a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_a5a1dc39-9907-4f5a-9099-69b95ce33605" xlink:to="loc_srt_NameOfMajorCustomerDomain_4964778d-d0d3-47ba-8352-5b2d97d0158a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ExternalCustomersMember_c3fca035-fa65-43bf-8d3c-11f7d67720c6" xlink:href="bkh-20210930.xsd#bkh_ExternalCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_4964778d-d0d3-47ba-8352-5b2d97d0158a" xlink:to="loc_bkh_ExternalCustomersMember_c3fca035-fa65-43bf-8d3c-11f7d67720c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_IntercompanyCustomersMember_858e8e81-9d95-45db-80ee-a5b9e111e9b9" xlink:href="bkh-20210930.xsd#bkh_IntercompanyCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_4964778d-d0d3-47ba-8352-5b2d97d0158a" xlink:to="loc_bkh_IntercompanyCustomersMember_858e8e81-9d95-45db-80ee-a5b9e111e9b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_4e86cba9-3d23-48f3-b267-07bb28855857" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7bcde4d3-5137-4ddd-9c23-2d34b5c33a88" xlink:to="loc_srt_ProductOrServiceAxis_4e86cba9-3d23-48f3-b267-07bb28855857" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_4e86cba9-3d23-48f3-b267-07bb28855857_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_4e86cba9-3d23-48f3-b267-07bb28855857" xlink:to="loc_srt_ProductsAndServicesDomain_4e86cba9-3d23-48f3-b267-07bb28855857_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_6ec13dd0-7d79-40dc-85ab-3a0bb3c87bec" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_4e86cba9-3d23-48f3-b267-07bb28855857" xlink:to="loc_srt_ProductsAndServicesDomain_6ec13dd0-7d79-40dc-85ab-3a0bb3c87bec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherMember_611d7f27-19e6-4e71-8c1f-31cc1bef7abc" xlink:href="bkh-20210930.xsd#bkh_OtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_6ec13dd0-7d79-40dc-85ab-3a0bb3c87bec" xlink:to="loc_bkh_OtherMember_611d7f27-19e6-4e71-8c1f-31cc1bef7abc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_452075f3-d7df-40fc-8512-7cd5a0ffc04c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7bcde4d3-5137-4ddd-9c23-2d34b5c33a88" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_452075f3-d7df-40fc-8512-7cd5a0ffc04c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_452075f3-d7df-40fc-8512-7cd5a0ffc04c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_452075f3-d7df-40fc-8512-7cd5a0ffc04c" xlink:to="loc_us-gaap_SegmentDomain_452075f3-d7df-40fc-8512-7cd5a0ffc04c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_19ce8e35-7c61-42f2-a392-0717c88d1701" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_452075f3-d7df-40fc-8512-7cd5a0ffc04c" xlink:to="loc_us-gaap_SegmentDomain_19ce8e35-7c61-42f2-a392-0717c88d1701" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_9d474cdb-1d84-43a9-abff-4a70c8770c2a" xlink:href="bkh-20210930.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_19ce8e35-7c61-42f2-a392-0717c88d1701" xlink:to="loc_bkh_ElectricUtilitiesMember_9d474cdb-1d84-43a9-abff-4a70c8770c2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_5b9d9f6c-40f9-4fb8-ad90-a7374fc43091" xlink:href="bkh-20210930.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_19ce8e35-7c61-42f2-a392-0717c88d1701" xlink:to="loc_bkh_GasUtilitiesMember_5b9d9f6c-40f9-4fb8-ad90-a7374fc43091" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PowerGenerationMember_3b042cb4-1695-436e-8a8f-7bbc75a68561" xlink:href="bkh-20210930.xsd#bkh_PowerGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_19ce8e35-7c61-42f2-a392-0717c88d1701" xlink:to="loc_bkh_PowerGenerationMember_3b042cb4-1695-436e-8a8f-7bbc75a68561" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MiningMember_e673050b-e277-484b-8c9a-35a78e588ffa" xlink:href="bkh-20210930.xsd#bkh_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_19ce8e35-7c61-42f2-a392-0717c88d1701" xlink:to="loc_bkh_MiningMember_e673050b-e277-484b-8c9a-35a78e588ffa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_3aac6587-3cb7-434f-8339-01655e1584d5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7bcde4d3-5137-4ddd-9c23-2d34b5c33a88" xlink:to="loc_srt_ConsolidationItemsAxis_3aac6587-3cb7-434f-8339-01655e1584d5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_3aac6587-3cb7-434f-8339-01655e1584d5_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_3aac6587-3cb7-434f-8339-01655e1584d5" xlink:to="loc_srt_ConsolidationItemsDomain_3aac6587-3cb7-434f-8339-01655e1584d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_bd8370b1-2eb7-484e-892a-e341d27dc8d3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_3aac6587-3cb7-434f-8339-01655e1584d5" xlink:to="loc_srt_ConsolidationItemsDomain_bd8370b1-2eb7-484e-892a-e341d27dc8d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_448a8d42-92c4-4d8d-8e4c-34b4a38aa36f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_bd8370b1-2eb7-484e-892a-e341d27dc8d3" xlink:to="loc_us-gaap_IntersegmentEliminationMember_448a8d42-92c4-4d8d-8e4c-34b4a38aa36f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationEliminationsMember_750abe47-c8c2-4db2-8b90-d47f1ab6e819" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidationEliminationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_bd8370b1-2eb7-484e-892a-e341d27dc8d3" xlink:to="loc_srt_ConsolidationEliminationsMember_750abe47-c8c2-4db2-8b90-d47f1ab6e819" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_fed926d6-d67f-4fab-a7cc-79328c4d2002" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_bd8370b1-2eb7-484e-892a-e341d27dc8d3" xlink:to="loc_us-gaap_CorporateNonSegmentMember_fed926d6-d67f-4fab-a7cc-79328c4d2002" xlink:type="arc" order="2"/>
  </link:definitionLink>
</link:linkbase>
