Lake County Illinois GISDownload In State Plane Projection Here . SSA and TIF boundaries are based on legal documents filed in the office of the Recorder of Deeds and on court orders. Mapping is based on the legal descriptions from those documents, which relate to existing parcel, municipal, township and PLSS features. Attributes include the district name and address. Update Frequency: This dataset is updated on a weekly basis.ArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/66b992cb984a46e1a2f005b0dfc71ddc_13engLake County Illinois Open Data PortalPublicSpecial Service Areas and Tax Increment Finance Areas [Illinois--Lake County]Web servicesIllinois--Lake CountyIllinoisLast Modified: 2026-01-04