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<import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
<import namespace="http://fasb.org/us-gaap/2022" schemaLocation="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd" />
<import namespace="http://xbrl.sec.gov/country/2022" schemaLocation="https://xbrl.sec.gov/country/2022/country-2022.xsd" />
<import namespace="http://xbrl.sec.gov/currency/2022" schemaLocation="https://xbrl.sec.gov/currency/2022/currency-2022.xsd" />
<import namespace="http://xbrl.sec.gov/exch/2022" schemaLocation="https://xbrl.sec.gov/exch/2022/exch-2022.xsd" />
<import namespace="http://xbrl.sec.gov/naics/2022" schemaLocation="https://xbrl.sec.gov/naics/2022/naics-2022.xsd" />
<import namespace="http://xbrl.sec.gov/sic/2022" schemaLocation="https://xbrl.sec.gov/sic/2022/sic-2022.xsd" />
<import namespace="http://xbrl.sec.gov/stpr/2022" schemaLocation="https://xbrl.sec.gov/stpr/2022/stpr-2022.xsd" />
<import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd" />
<import namespace="http://www.xbrl.org/2009/role/net" schemaLocation="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd" />
<import namespace="http://www.xbrl.org/2009/arcrole/fact-explanatoryFact" schemaLocation="http://www.xbrl.org/lrr/arcrole/factExplanatory-2009-12-16.xsd" />
<import namespace="http://xbrl.sec.gov/dei/2022" schemaLocation="https://xbrl.sec.gov/dei/2022/dei-2022.xsd" />
<import namespace="http://fasb.org/us-types/2022" schemaLocation="https://xbrl.fasb.org/us-gaap/2022/elts/us-types-2022.xsd" />
<import namespace="http://fasb.org/srt-types/2022" schemaLocation="https://xbrl.fasb.org/srt/2022/elts/srt-types-2022.xsd" />
<import namespace="http://fasb.org/srt/2022" schemaLocation="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd" />
<import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd" />
<element name="ConsolidatedStatementsOfEarningsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ConsolidatedStatementsOfEarningsAbstract" substitutionGroup="xbrli:item" />
<element name="GasMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_GasMember" substitutionGroup="xbrli:item" />
<element name="ElectricMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ElectricMember" substitutionGroup="xbrli:item" />
<element name="CommonStockEquity" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="utl_CommonStockEquity" substitutionGroup="xbrli:item" xbrli:balance="credit" />
<element name="NoncurrentAssetsOtherThanPropertyPlantAndEquipment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="utl_NoncurrentAssetsOtherThanPropertyPlantAndEquipment" substitutionGroup="xbrli:item" xbrli:balance="debit" />
<element name="PublicUtilitiesPropertyPlantAndEquipmentGas" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="utl_PublicUtilitiesPropertyPlantAndEquipmentGas" substitutionGroup="xbrli:item" xbrli:balance="debit" />
<element name="IncreaseDecreaseInGasInventoryFinancing" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_IncreaseDecreaseInGasInventoryFinancing" substitutionGroup="xbrli:item" xbrli:balance="debit" />
<element name="IncreaseDecreaseInCapitalLeaseObligations" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_IncreaseDecreaseInCapitalLeaseObligations" substitutionGroup="xbrli:item" xbrli:balance="credit" />
<element name="NoncashInvestingActivityAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_NoncashInvestingActivityAbstract" substitutionGroup="xbrli:item" />
<element name="ChangeInDeferredRegulatoryAndOtherCharges" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_ChangeInDeferredRegulatoryAndOtherCharges" substitutionGroup="xbrli:item" xbrli:balance="debit" />
<element name="DividendsDeclaredPerShareAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_DividendsDeclaredPerShareAbstract" substitutionGroup="xbrli:item" />
<element name="DisclosureOfDividendsDeclaredAndPaidTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_DisclosureOfDividendsDeclaredAndPaidTextBlock" substitutionGroup="xbrli:item" />
<element name="SupplyCommitmentPolicyTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_SupplyCommitmentPolicyTextBlock" substitutionGroup="xbrli:item" />
<element name="NatureOfOperationsPolicyTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_NatureOfOperationsPolicyTextBlock" substitutionGroup="xbrli:item" />
<element name="AllowanceForDoubtfulAccountsPolicyTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_AllowanceForDoubtfulAccountsPolicyTextBlock" substitutionGroup="xbrli:item" />
<element name="DeferredCompensationPlanMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_DeferredCompensationPlanMember" substitutionGroup="xbrli:item" />
<element name="ComponentsOfGasOperatingRevenueAndElectricOperatingRevenueTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_ComponentsOfGasOperatingRevenueAndElectricOperatingRevenueTableTextBlock" substitutionGroup="xbrli:item" />
<element name="AllowanceForDoubtfulAccountsTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_AllowanceForDoubtfulAccountsTableTextBlock" substitutionGroup="xbrli:item" />
<element name="UnbilledAccountsReceivableTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_UnbilledAccountsReceivableTableTextBlock" substitutionGroup="xbrli:item" />
<element name="ScheduleOfOtherAccountsReceivableTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_ScheduleOfOtherAccountsReceivableTableTextBlock" substitutionGroup="xbrli:item" />
<element name="ScheduleOfFutureMinimumPaymentsForObligationsTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_ScheduleOfFutureMinimumPaymentsForObligationsTableTextBlock" substitutionGroup="xbrli:item" />
<element name="ScheduleOfCapitalLeasesObligationsTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_ScheduleOfCapitalLeasesObligationsTableTextBlock" substitutionGroup="xbrli:item" />
<element name="SignificantAccountingPoliciesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_SignificantAccountingPoliciesTable" substitutionGroup="xbrldt:hypercubeItem" />
<element name="EnvironmentalAndRateCaseCostsAndOtherExpendituresMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_EnvironmentalAndRateCaseCostsAndOtherExpendituresMember" substitutionGroup="xbrli:item" />
<element name="PeriodTypeAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_PeriodTypeAxis" substitutionGroup="xbrldt:dimensionItem" />
<element name="PeriodTypeDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_PeriodTypeDomain" substitutionGroup="xbrli:item" />
<element name="SignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_SignificantAccountingPoliciesLineItems" substitutionGroup="xbrli:item" />
<element name="LengthOfPipeline" type="dtr-types:lengthItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_LengthOfPipeline" substitutionGroup="xbrli:item" />
<element name="NumberOfSubsidiaries" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="utl_NumberOfSubsidiaries" substitutionGroup="xbrli:item" />
<element name="CashDeposits" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="utl_CashDeposits" substitutionGroup="xbrli:item" xbrli:balance="debit" />
<element name="HardshipAccountsInRegulatoryAssets" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="utl_HardshipAccountsInRegulatoryAssets" substitutionGroup="xbrli:item" xbrli:balance="debit" />
<element name="PeriodAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_PeriodAxis" substitutionGroup="xbrldt:dimensionItem" />
<element name="PeriodDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_PeriodDomain" substitutionGroup="xbrli:item" />
<element name="NewEnglandMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_NewEnglandMember" substitutionGroup="xbrli:item" />
<element name="UtilitiesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_UtilitiesMember" substitutionGroup="xbrli:item" />
<element name="OtherSubsidiariesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_OtherSubsidiariesMember" substitutionGroup="xbrli:item" />
<element name="FitchburgGasAndElectricLightCompanyMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_FitchburgGasAndElectricLightCompanyMember" substitutionGroup="xbrli:item" />
<element name="ElectricAndGasDivisionMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ElectricAndGasDivisionMember" substitutionGroup="xbrli:item" />
<element name="OtherDeferredChargesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_OtherDeferredChargesMember" substitutionGroup="xbrli:item" />
<element name="OperatingRevenuesAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_OperatingRevenuesAbstract" substitutionGroup="xbrli:item" />
<element name="ResidentialMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ResidentialMember" substitutionGroup="xbrli:item" />
<element name="CommercialAndIndustrialMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_CommercialAndIndustrialMember" substitutionGroup="xbrli:item" />
<element name="OperatingRevenuesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_OperatingRevenuesLineItems" substitutionGroup="xbrli:item" />
<element name="BilledAndUnbilledRevenueMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_BilledAndUnbilledRevenueMember" substitutionGroup="xbrli:item" />
<element name="RateAdjustmentMechanismRevenueMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_RateAdjustmentMechanismRevenueMember" substitutionGroup="xbrli:item" />
<element name="GasSegmentMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_GasSegmentMember" substitutionGroup="xbrli:item" />
<element name="AllowanceForDoubtfulAccountsIncludedInAccountsReceivableNetdetailAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_AllowanceForDoubtfulAccountsIncludedInAccountsReceivableNetdetailAbstract" substitutionGroup="xbrli:item" />
<element name="ComponentsOfAccruedRevenueAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ComponentsOfAccruedRevenueAbstract" substitutionGroup="xbrli:item" />
<element name="RegulatoryAssetMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_RegulatoryAssetMember" substitutionGroup="xbrli:item" />
<element name="ComponentsOfExchangeGasReceivableAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ComponentsOfExchangeGasReceivableAbstract" substitutionGroup="xbrli:item" />
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<element name="NorthernUtilitiesIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_NorthernUtilitiesIncMember" substitutionGroup="xbrli:item" />
<element name="ReceivablesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ReceivablesLineItems" substitutionGroup="xbrli:item" />
<element name="ComponentsOfGasInventoryAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ComponentsOfGasInventoryAbstract" substitutionGroup="xbrli:item" />
<element name="RegulatoryAssetsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_RegulatoryAssetsAbstract" substitutionGroup="xbrli:item" />
<element name="ElectricUtilitiesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ElectricUtilitiesMember" substitutionGroup="xbrli:item" />
<element name="IncomeTaxesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_IncomeTaxesMember" substitutionGroup="xbrli:item" />
<element name="EnvironmentalMattersMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_EnvironmentalMattersMember" substitutionGroup="xbrli:item" />
<element name="ContractualObligationsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ContractualObligationsMember" substitutionGroup="xbrli:item" />
<element name="RegulatoryLiabilitiesAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_RegulatoryLiabilitiesAbstract" substitutionGroup="xbrli:item" />
<element name="RateAdjustmentMechanismsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_RateAdjustmentMechanismsMember" substitutionGroup="xbrli:item" />
<element name="IncomeTaxRelatedLiabilitiesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_IncomeTaxRelatedLiabilitiesMember" substitutionGroup="xbrli:item" />
<element name="FairValueOfMarketableSecuritiesAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_FairValueOfMarketableSecuritiesAbstract" substitutionGroup="xbrli:item" />
<element name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTablTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTablTable" substitutionGroup="xbrldt:hypercubeItem" />
<element name="InvestmentTypesAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_InvestmentTypesAxis" substitutionGroup="xbrldt:dimensionItem" />
<element name="InvestmentsTypeCategorizationDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_InvestmentsTypeCategorizationDomain" substitutionGroup="xbrli:item" />
<element name="DivestitureMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_DivestitureMember" substitutionGroup="xbrli:item" />
<element name="RenewableEnergyPortfolioRequirementMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_RenewableEnergyPortfolioRequirementMember" substitutionGroup="xbrli:item" />
<element name="ContractualObligationLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_ContractualObligationLineItems" substitutionGroup="xbrli:item" />
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<element name="GroupFiveMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_GroupFiveMember" substitutionGroup="xbrli:item" />
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<element name="GroupFourMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_GroupFourMember" substitutionGroup="xbrli:item" />
<element name="UnitilEnergySystemsIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_UnitilEnergySystemsIncMember" substitutionGroup="xbrli:item" />
<element name="GraniteStateGasTransmissionIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_GraniteStateGasTransmissionIncMember" substitutionGroup="xbrli:item" />
<element name="UnitilRealtyCorpMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_UnitilRealtyCorpMember" substitutionGroup="xbrli:item" />
<element name="SeniorNotesSixPointSevenFivePercentDueNovemberThirtyTwentyTwentyThreeMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="utl_SeniorNotesSixPointSevenFivePercentDueNovemberThirtyTwentyTwentyThreeMember" substitutionGroup="xbrli:item" />
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