| CompensationExplanation/CompensationExplanationGrp/PersonNm | 0 | Ward Miller |
| CompensationExplanation/CompensationExplanationGrp/ShortExplanationTxt | 0 | Salary for Director |
| IRS990EZ/ActivitiesNotPreviouslyRptInd | 0 | false |
| IRS990EZ/BooksInCareOfDetail/PersonNm | 0 | Ward Miller |
| IRS990EZ/BooksInCareOfDetail/PhoneNum | 0 | 7733348800 |
| IRS990EZ/BooksInCareOfDetail/USAddress/AddressLine1Txt | 0 | 4410 N Ravenswood |
| IRS990EZ/BooksInCareOfDetail/USAddress/CityNm | 0 | Chicago |
| IRS990EZ/BooksInCareOfDetail/USAddress/StateAbbreviationCd | 0 | IL |
| IRS990EZ/BooksInCareOfDetail/USAddress/ZIPCd | 0 | 60640 |
| IRS990EZ/CashSavingsAndInvestmentsGrp/BOYAmt | 0 | 121385 |
| IRS990EZ/CashSavingsAndInvestmentsGrp/EOYAmt | 0 | 196660 |
| IRS990EZ/ChgMadeToOrgnzngDocNotRptInd | 0 | false |
| IRS990EZ/ContributionsGiftsGrantsEtcAmt | 0 | 184828 |
| IRS990EZ/DonorAdvisedFndsInd | 0 | false |
| IRS990EZ/EngagedInExcessBenefitTransInd | 0 | false |
| IRS990EZ/ExcessOrDeficitForYearAmt | 0 | 74330 |
| IRS990EZ/FeesAndOtherPymtToIndCntrctAmt | 0 | 3819 |
| IRS990EZ/FiledScheduleAInd | 0 | true |
| IRS990EZ/ForeignFinancialAccountInd | 0 | false |
| IRS990EZ/ForeignOfficeInd | 0 | false |
| IRS990EZ/Form1120PolFiledInd | 0 | false |
| IRS990EZ/Form990TotalAssetsGrp/BOYAmt | 0 | 121385 |
| IRS990EZ/Form990TotalAssetsGrp/EOYAmt | 0 | 196660 |
| IRS990EZ/FundraisingGrossIncomeAmt | 0 | 1034 |
| IRS990EZ/GrossReceiptsAmt | 0 | 195618 |
| IRS990EZ/InfoInScheduleOPartIIInd | 0 | X |
| IRS990EZ/InfoInScheduleOPartIInd | 0 | X |
| IRS990EZ/LandAndBuildingsGrp/BOYAmt | 0 | 0 |
| IRS990EZ/LandAndBuildingsGrp/EOYAmt | 0 | 0 |
| IRS990EZ/LobbyingActivitiesInd | 0 | false |
| IRS990EZ/MadeLoansToFromOfficersInd | 0 | false |
| IRS990EZ/MembershipDuesAmt | 0 | 9725 |
| IRS990EZ/MethodOfAccountingCashInd | 0 | X |
| IRS990EZ/NetAssetsOrFundBalancesBOYAmt | 0 | 121225 |
| IRS990EZ/NetAssetsOrFundBalancesEOYAmt | 0 | 195555 |
| IRS990EZ/NetAssetsOrFundBalancesGrp/BOYAmt | 0 | 121225 |
| IRS990EZ/NetAssetsOrFundBalancesGrp/EOYAmt | 0 | 195555 |
| IRS990EZ/OccupancyRentUtltsAndMaintAmt | 0 | 12731 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 0 | 40.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 1 | 5.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 2 | 5.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 3 | 5.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 4 | 5.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 5 | 2.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 6 | 2.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 7 | 2.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 8 | 2.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 9 | 2.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 10 | 2.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/AverageHrsPerWkDevotedToPosRt | 11 | 2.00 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 0 | 67814 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 1 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 2 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 3 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 4 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 5 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 6 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 7 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 8 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 9 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 10 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/CompensationAmt | 11 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 0 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 1 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 2 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 3 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 4 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 5 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 6 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 7 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 8 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 9 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 10 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/EmployeeBenefitProgramAmt | 11 | 0 |
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| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 1 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 2 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 3 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 4 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 5 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 6 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 7 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 8 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 9 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 10 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/ExpenseAccountOtherAllwncAmt | 11 | 0 |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 0 | Ward Miller |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 1 | Brad Suster |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 2 | Jacob Kaplan |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 3 | Andy Thornton |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 4 | Debbie Dodge |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 5 | Stuart Berman |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 6 | Joyce Jackson |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 7 | Andrea Reed |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 8 | Susannah Ribstein |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 9 | Charles Vinz |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 10 | Cathie Bond |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/PersonNm | 11 | Emily Nielsen |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 0 | Executive Director |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 1 | President |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 2 | Vice President |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 3 | Treasurer |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 4 | Secretary |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 5 | Board Member |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 6 | Board Member |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 7 | Board Member |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 8 | Board Member |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 9 | Board Member |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 10 | Board Member |
| IRS990EZ/OfficerDirectorTrusteeEmplGrp/TitleTxt | 11 | Board Member |
| IRS990EZ/OperateHospitalInd | 0 | false |
| IRS990EZ/Organization501c3Ind | 0 | X |
| IRS990EZ/OrganizationDissolvedEtcInd | 0 | false |
| IRS990EZ/OrganizationHadUBIInd | 0 | false |
| IRS990EZ/OtherAssetsTotalDetail/BOYAmt | 0 | 0 |
| IRS990EZ/OtherAssetsTotalDetail/EOYAmt | 0 | 0 |
| IRS990EZ/OtherExpensesTotalAmt | 0 | 18671 |
| IRS990EZ/OtherRevenueTotalAmt | 0 | 31 |
| IRS990EZ/PartVIHghstPdCntrctProfSrvcTxt | 0 | NONE |
| IRS990EZ/PartVIOfCompOfHghstPdEmplTxt | 0 | NONE |
| IRS990EZ/PoliticalCampaignActyInd | 0 | false |
| IRS990EZ/PrimaryExemptPurposeTxt | 0 | See Schedule O |
| IRS990EZ/PrintingPublicationsPostageAmt | 0 | 4698 |
| IRS990EZ/ProgramSrvcAccomplishmentGrp/DescriptionProgramSrvcAccomTxt | 0 | Advocated for the preservation of multiple buildings that were of historical importance to Chicago |
| IRS990EZ/ProgramSrvcAccomplishmentGrp/GrantsAndAllocationsAmt | 0 | 130000 |
| IRS990EZ/ProgramSrvcAccomplishmentGrp/ProgramServiceExpensesAmt | 0 | 121290 |
| IRS990EZ/ProhibitedTaxShelterTransInd | 0 | false |
| IRS990EZ/RelatedOrganizationCtrlEntInd | 0 | false |
| IRS990EZ/SalariesOtherCompEmplBnftAmt | 0 | 81369 |
| IRS990EZ/SchoolOperatingInd | 0 | false |
| IRS990EZ/SpecialEventsNetIncomeLossAmt | 0 | 1034 |
| IRS990EZ/StatesWhereCopyOfReturnIsFldCd | 0 | IL |
| IRS990EZ/SubjectToProxyTaxInd | 0 | false |
| IRS990EZ/SumOfTotalLiabilitiesGrp/BOYAmt | 0 | 160 |
| IRS990EZ/SumOfTotalLiabilitiesGrp/EOYAmt | 0 | 1105 |
| IRS990EZ/TanningServicesProvidedInd | 0 | false |
| IRS990EZ/TotalExpensesAmt | 0 | 121288 |
| IRS990EZ/TotalProgramServiceExpensesAmt | 0 | 121290 |
| IRS990EZ/TotalRevenueAmt | 0 | 195618 |
| IRS990EZ/TransactionWithControlEntInd | 0 | false |
| IRS990EZ/TrnsfrExmptNonChrtblRltdOrgInd | 0 | false |
| IRS990EZ/TypeOfOrganizationCorpInd | 0 | X |
| IRS990EZ/WebsiteAddressTxt | 0 | www.preservationchicago.org |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearAmt | 0 | 195587 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus1YearAmt | 0 | 171873 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus2YearsAmt | 0 | 37337 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus3YearsAmt | 0 | 136771 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/CurrentTaxYearMinus4YearsAmt | 0 | 110279 |
| IRS990ScheduleA/GiftsGrantsContriRcvd170Grp/TotalAmt | 0 | 651847 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/CurrentTaxYearAmt | 0 | 31 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/CurrentTaxYearMinus1YearAmt | 0 | 59 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/CurrentTaxYearMinus4YearsAmt | 0 | 62 |
| IRS990ScheduleA/GrossInvestmentIncome170Grp/TotalAmt | 0 | 152 |
| IRS990ScheduleA/OtherIncome170Grp/CurrentTaxYearMinus2YearsAmt | 0 | 74 |
| IRS990ScheduleA/OtherIncome170Grp/CurrentTaxYearMinus3YearsAmt | 0 | 865 |
| IRS990ScheduleA/OtherIncome170Grp/CurrentTaxYearMinus4YearsAmt | 0 | 1126 |
| IRS990ScheduleA/OtherIncome170Grp/TotalAmt | 0 | 2065 |
| IRS990ScheduleA/PublicOrganization170Ind | 0 | X |
| IRS990ScheduleA/PublicSupportCY170Pct | 0 | 0.61320 |
| IRS990ScheduleA/PublicSupportPY170Pct | 0 | 0.99570 |
| IRS990ScheduleA/PublicSupportTotal170Amt | 0 | 401090 |
| IRS990ScheduleA/SubstantialContributorsTotAmt | 0 | 250757 |
| IRS990ScheduleA/ThirtyThrPctSuprtTestsCY170Ind | 0 | X |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearAmt | 0 | 195587 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus1YearAmt | 0 | 171873 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus2YearsAmt | 0 | 37337 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus3YearsAmt | 0 | 136771 |
| IRS990ScheduleA/TotalCalendarYear170Grp/CurrentTaxYearMinus4YearsAmt | 0 | 110279 |
| IRS990ScheduleA/TotalCalendarYear170Grp/TotalAmt | 0 | 651847 |
| IRS990ScheduleA/TotalSupportAmt | 0 | 654064 |
| IRS990ScheduleB/ContributorInformationGrp/ContributorBusinessName/BusinessNameLine1 | 0 | RESTRICTED |
| IRS990ScheduleB/ContributorInformationGrp/ContributorNum | 0 | RESTRICTED |
| IRS990ScheduleB/ContributorInformationGrp/ContributorUSAddress/AddressLine1 | 0 | RESTRICTED |
| IRS990ScheduleB/ContributorInformationGrp/ContributorUSAddress/AddressLine2 | 0 | RESTRICTED |
| IRS990ScheduleB/ContributorInformationGrp/ContributorUSAddress/City | 0 | RESTRICTED |
| IRS990ScheduleB/ContributorInformationGrp/ContributorUSAddress/State | 0 | RESTRICTED |
| IRS990ScheduleB/ContributorInformationGrp/ContributorUSAddress/ZIPCode | 0 | RESTRICTED |
| IRS990ScheduleB/ContributorInformationGrp/TotalContributionsAmt | 0 | RESTRICTED |
| IRS990ScheduleO/SupplementalInformationDetail/ExplanationTxt | 0 | Form 990-EZ, Part III, Primary Exempt Purpose - To Advocate for the preservation of Chicagos historic architectureForm 990-EZ, Part V, Information Regarding Personal Benefit Contracts:The organization did not, during the year, receive any funds, directly or indirectly, to pay premiums on a personal benefit contract.The organization did not, during the year, pay any premiums, directly or indirectly, on a personal benefit contract |
| IRS990ScheduleO/SupplementalInformationDetail/ExplanationTxt | 1 | Description AmountInterest Income 31 |
| IRS990ScheduleO/SupplementalInformationDetail/ExplanationTxt | 2 | Description AmountEvent Expenses 2,760Technology Expenses 1,748Insurance 1,926Travel and Entertainment 9,373Marketing 1,701Office 1,163 |
| IRS990ScheduleO/SupplementalInformationDetail/ExplanationTxt | 3 | Category Beginning of Year End of YearCredit Card Payable 160 1,105 |
| IRS990ScheduleO/SupplementalInformationDetail/FormAndLineReferenceDesc | 0 | General explanation attachment |
| IRS990ScheduleO/SupplementalInformationDetail/FormAndLineReferenceDesc | 1 | Description of other revenue Part I line 8 |
| IRS990ScheduleO/SupplementalInformationDetail/FormAndLineReferenceDesc | 2 | Description of other expenses Part I line 16 |
| IRS990ScheduleO/SupplementalInformationDetail/FormAndLineReferenceDesc | 3 | Description of total liabilities Part II line 26 |
| ReturnHeader/BuildTS | 0 | 2018-03-14 21:41:22Z |
| ReturnHeader/BusinessOfficerGrp/DiscussWithPaidPreparerInd | 0 | true |
| ReturnHeader/BusinessOfficerGrp/PersonNm | 0 | Ward Miller |
| ReturnHeader/BusinessOfficerGrp/PersonTitleTxt | 0 | Executive Direc |
| ReturnHeader/BusinessOfficerGrp/PhoneNum | 0 | 7733348800 |
| ReturnHeader/BusinessOfficerGrp/SignatureDt | 0 | 2017-10-24 |
| ReturnHeader/Filer/BusinessName/BusinessNameLine1Txt | 0 | Preservation Chicago |
| ReturnHeader/Filer/BusinessNameControlTxt | 0 | PRES |
| ReturnHeader/Filer/EIN | 0 | 010674228 |
| ReturnHeader/Filer/USAddress/AddressLine1Txt | 0 | 4410 N Ravenswood |
| ReturnHeader/Filer/USAddress/CityNm | 0 | Chicago |
| ReturnHeader/Filer/USAddress/StateAbbreviationCd | 0 | IL |
| ReturnHeader/Filer/USAddress/ZIPCd | 0 | 60640 |
| ReturnHeader/FilingSecurityInformation/AtSubmissionCreationDeviceId | 0 | 67A0C381C291D5717E92B86EB2B9620ABDC22205 |
| ReturnHeader/FilingSecurityInformation/AtSubmissionFilingDeviceId | 0 | 67A0C381C291D5717E92B86EB2B9620ABDC22205 |
| ReturnHeader/FilingSecurityInformation/FederalOriginalSubmissionId | 0 | 1572322017310vwydymd |
| ReturnHeader/FilingSecurityInformation/FederalOriginalSubmissionIdDt | 0 | 2017-11-06 |
| ReturnHeader/FilingSecurityInformation/FilingLicenseTypeCd | 0 | P |
| ReturnHeader/FilingSecurityInformation/IPAddress/IPv4AddressTxt | 0 | 67.173.191.32 |
| ReturnHeader/FilingSecurityInformation/IPDt | 0 | 2017-11-06 |
| ReturnHeader/FilingSecurityInformation/IPTm | 0 | 22:11:44 |
| ReturnHeader/PreparerFirmGrp/PreparerFirmEIN | 0 | 461788730 |
| ReturnHeader/PreparerFirmGrp/PreparerFirmName/BusinessNameLine1Txt | 0 | Ledger General Inc |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/AddressLine1Txt | 0 | 5100 N Ravenswood Ave Ste 104 |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/CityNm | 0 | Chicago |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/StateAbbreviationCd | 0 | IL |
| ReturnHeader/PreparerFirmGrp/PreparerUSAddress/ZIPCd | 0 | 60640 |
| ReturnHeader/PreparerPersonGrp/PhoneNum | 0 | 7738751843 |
| ReturnHeader/PreparerPersonGrp/PreparationDt | 0 | 2017-10-24 |
| ReturnHeader/PreparerPersonGrp/PreparerPersonNm | 0 | Martin McCaffrey |
| ReturnHeader/ReturnTs | 0 | 2017-10-24T13:08:19-04:00 |
| ReturnHeader/ReturnTypeCd | 0 | 990EZ |
| ReturnHeader/TaxPeriodBeginDt | 0 | 2016-01-01 |
| ReturnHeader/TaxPeriodEndDt | 0 | 2016-12-31 |
| ReturnHeader/TaxYr | 0 | 2016 |