This is a Cook County Feature class of Unincorporated Zoning District Boundaries (Aggregate). This data is provided by the Cook County Dept. Of Building and Zoning and is maintained by the Cook County Zoning Board of Appeals.
Only unincorporated district boundaries are available, please contact specific municipalities for questions regarding incorporated municipal zoning districts.

This data set includes property locations and attached spatial data for all Cook County parcels. Spatial matching was based on parcel centroids. Older properties may be missing latitude and longitude data because they are not contained in the most recent parcel shape layer. Brand new properties may be missing a mailing/property address because the postal service has not yet assigned the property an address. Data attached to each PIN is the most recent available. For example, Census tract data is drawn from the 2014-2018 5-year American Community Survey.

The code and sources used to construct this data can be located on GitLab. See data notes for link.

The Street Midlines in this feature class represent the interpreted midline between the compiled edges of pavement. Unimproved rights-of-way are also included in this database.

Data last updated September 8th, 2011

This dataset is updated nightly. For extended information about Lobbyist Activities in Cook County IL, visit the Cook County Clerk's Lobbyist search: http://lobbyist.cookcountyclerk.com/Public/SearchHome.aspx

The feature class Right-of-Way indicates tax exempt rights-of-way digitized from recorded plats.

Neighborhoods play an important role in residential property assessment. Single-family and residential multi-family property assessments are sensitive to neighborhood boundaries. Neighborhoods are nearly always used in statistical regression models to produce initial assessed values, and comparable properties are nearly always selected from within neighborhoods for the purposes of appeal. See data notes for additional information.

Neighborhood polygons used by the Cook County Assessor's Office for valuation and reporting. These neighborhoods are specific to the Assessor. They are intended to represent homogenous housing submarkets, NOT Chicago community areas or municipalities.

These neighborhoods were reconstructed from individual parcels using spatial buffering and simplification. The full transformation script can be found on the Assessor's GitHub.

The Parcel 2021 feature contains tax parcel polygons for the 2021 property tax assessment at the County. This feature reflects tax parcel polygons as they existed from 1/1/2021 through 12/31/2021. An ESRI Service is available at: https://hub-cookcountyil.opendata.arcgis.com/datasets/34021b4f3b834a69bf737e6c3344888e_0