Parcels with tax assessor data for SSMMA region. See Code Definitions for Cook County parcel classification details.CAVEAT EMPTOR: Cook County data from 2016, Will County data from 2017.We are currently in the process of collecting Cook County data and processing Will County data for 2019.For up-to-date parcel tax records, visit the Cook County GIS Viewer or Will County GIS Viewer, or access the Cook County Tax Assessor's databases [1] [2] or the Will County Tax Assessor's Office.Municipalities in SSMMA's GIS Consortium may contact the GIS staff if more recent data is available to display on municipal viewers.

Forest Preserve District of Cook County boundaries. To view or use these shapefiles, compression software and special GIS software, such as ESRI ArcGIS, is required.

Private-facing version: https://ssmma-gis.maps.arcgis.com/home/item.html?id=e391d81589c149919cd84a5088d46e80Update log:Jun. 28, 2024 - fixed an issue where taxpayer data showed

Hydrographic data was collected for all of Cook County. Significant flowing and standing water features that were visible on the aerial photography were stereocompiled from 1998 aerial photography. The hydrographic midline data set represents, as a single line, the interpreted midline of flowing water features as seen on the aerial photography. The hydrographic midline data layer is used to show the location of the midline of natural drainage features, and is connected to polygonal (standing) hydrographic features such as lakes and ponds. The midline data layer also includes drainage features less than five feet in width, which were not included in the polygon hydrography data set. Midlines were added to water bodies such as double-line rivers to maintain the linear connectivity of the hydrographic network. Where the course of linear features (such as streams and rivers) in the hydrographic midline layer could not be compiled photogrammetrically due to being obscured by other features (such as vegetation or shadows), the obscured line segment was coded as "interpreted". In some cases, a flowing water feature may have run through an underground drain or culvert or its course otherwise obscured from view on the aerial photography. For such cases, in order to maintain linear connectivity of the features, its path was also interpreted and coded as such. Some hydrographic data was provided by the City of Chicago and incorporated into this data layer. These hydrographic data layers are modeled and stored as a network coverage containing polygons and/or lines. This midline data layer was created out of need by Cook County to develop a hydrographic layer in which water features are represented as single lines. The intended primary use of this data layer is for small-scale mapping and networking. The hydrographic midline layer was intersected with the street midline and railroad data layers to create nodes in the coverage model. It was also intersected with the bridge polygon data layer. Where hydrographic midline segments fall within a bridge polygon, they have been given a grade separation code of zero (0) to indicate the water level is technically "at grade". Hydrographic attributes include feature name, tax map name, and type. The primary source of the attribute information was the Cook County Highway Department database. Hydrographic names and alias IDs are linked to lookup tables based on the hydrographic name ID attribute.

The Parcel 2020 feature contains tax parcel polygons for the 2020 property tax assessment at the County. This feature reflects tax parcel polygons as they existed from 1/1/2020 through 12/31/2020. An ESRI Service is available at: https://hub-cookcountyil.opendata.arcgis.com/datasets/577d80fcbf0441a780ecdfd9e1b6b5c2_0/explore

Shelters within the Forest Preserve District of Cook County. To view or use these shapefiles, compression software and special GIS software, such as ESRI ArcGIS, is required.

A complete, historic universe of Cook County parcels with attached geographic, governmental, and spatial data.

When working with Parcel Index Numbers (PINs) make sure to zero-pad them to 14 digits. Some datasets may lose leading zeros for PINs when downloaded.

Additional notes:

• Non-taxing district data is attached via spatial join (st_contains) to each parcel's centroid.
• Tax district data (school district, park district, municipality, etc.) are attached by a parcel's assigned tax code.
• Centroids are based on Cook County parcel shapefiles.
• Older properties may be missing coordinates and thus also missing attached spatial data (usually they are missing a parcel boundary in the shapefile).
• Newer properties may be missing a mailing or property address, as they need to be assigned one by the postal service.
• This dataset contains data for the current tax year, which may not yet be complete or final. Assessed values for any given year are subject to change until review and certification of values by the Cook County Board of Review, though there are a few rare circumstances where values may change for the current or past years after that.
• Rowcount for a given year is final once the Assessor has certified the assessment roll all townships.
• Data will be updated monthly.
• Depending on the time of year, some third-party and internal data will be missing for the most recent year. Assessments mailed this year represent values from last year, so this isn't an issue. By the time the Data Department models values for this year, those data will have populated.
• Current property class codes, their levels of assessment, and descriptions can be found on the Assessor's website. Note that class codes details can change across time.
• Due to discrepancies between the systems used by the Assessor and Clerk's offices, tax_district_code is not currently up-to-date in this table.

Read about the Assessor's 2025 Open Data Refresh.

Cook County GIS Dept map of Lake View, North & West Townships in a pdf format. Includes streets and municipalities.

Fishing lakes in Cook County with contours. To view or use these shapefiles, compression software and special GIS software, such as ESRI ArcGIS, is required

The Public Land Survey System (PLSS) is the way land in the United States is subdivided, it forms the foundation of Cook County's cadastral system for identifying and locating land records. Tax parcels are identified using township and section notation, in a modified format. The PLSS serves as a way for users to navigate the parcel geodatabase. This PLSS feature data set is intended to correspond to tax pages on the Cook County Tax Maps. They should not be used for measurement or surveyor purposes. In addition, the parcel attributes PINA (area/township) and PINSA (subarea/section) do not necessarily correspond to the PLSS township and section polygon in which a given parcel resides. The PLSS data is modeled as a single composite network coverage that encompasses townships (area), sections (subarea), quarter sections, and half quarter section. Tax map pages, which typically correspond to half quarter sections (in an east-west split), are modeled as a region subclass in the LANDFABRIC layer. If an indigenous people's reserve was present on the tax map, it was digitized to create subpolygons of the half-quarter section, and those polygons were attributed with the name of the reserve. Within this PLSS data set, a half-quarter section is the smallest polygon unit, except in cases where an Indigenous People's Reserve line is present. The cadastral data for Cook County have previously not been digital nor automated. This project is the initial automation for this information. This database was designed to represent a continuous, non-overlapping spatial database accounting for all land area in Cook County.The PLSS is updated as needed.

The Parcel 2005 feature contains tax parcel polygons for the 2005 property tax assessment at the County. This feature reflects tax parcel polygons as they existed from 1/1/2005 through 12/31/2005. Each parcel is uniquely identified with a Property Index Number (PIN).

description: Groves within the Forest Preserve District of Cook County. To view or use these shapefiles, compression software and special GIS software, such as ESRI ArcGIS, is required.; abstract: Groves within the Forest Preserve District of Cook County. To view or use these shapefiles, compression software and special GIS software, such as ESRI ArcGIS, is required.

Forest Preserve District of Cook County boundaries. To view or use these shapefiles, compression software and special GIS software, such as ESRI ArcGIS, is required.

KML file of private schools located in Cook County. To view or use these files, special GIS software such as Google Earth is required.

Suburban Cook County Election Precincts maintained by the Cook County Clerk's Election Department. Not included are the City of Chicago Election Precincts which are maintained by the Chicago Board Of Elections. An ArcGIS Service is available at: https://hub-cookcountyil.opendata.arcgis.com/datasets/0e91b48d49744346be343f0cb99d25bd_0/

Voting District Project of the Census Redistricting Data Program commenced in Summer of 2017 to establish the state’s Voting precincts within the bureau’s tiger geography. The initial phase used the Bureau’s GUPS plugin for QGIS to update the districts from the 2010 round, and then a secondary verification phase took place to ensure the updated voting districts were properly enacted into Tiger geographic files. A post census effort took place in December 2021 to cut the number of precincts down countywide to 1430. Election Data Services conducted Phase 2 of the Census Redistricting Data Program for the State of Illinois, as well as implemented changes made post census in Cook County.

Precincts are updated as needed before every election by the Cook County Clerk's Elections Department.

KML file of Forest Preserve District of Cook County boundaries. To view or use these files, special GIS software such as Google Earth is required

KML file of trails within the Forest Preserve District of Cook County. To view or use these files, special GIS software such as Google Earth is required

Historic land, building, and total assessed values for all Cook County parcels appealed with the Board of Review, from 2010 to present. The Board of Review uses these values for reporting, evaluating assessment performance over time, and research.

When working with Parcel Index Numbers (PINs) make sure to zero-pad them to 14 digits. Some datasets may lose leading zeros for PINs when downloaded

This data is parcel-level. Each row contains the assessed values for a single PIN for a single year. Important notes: • Assessed values are available when the Board of Review closes appeals and certifies the values. • The values in this data are assessed values, NOT market values. Assessed values must be adjusted by their level of assessment (https://prodassets.cookcountyassessor.com/s3fs-public/form_documents/classcode.pdf) to arrive at market value. Note that levels of assessment may have changed throughout the time period covered by this data set. • This data set will be updated when each township is certified. However, note that there may be discrepancies between the Board of Review’s data and the Assessor's site and this data set, as each pull from a slightly different system. • Current property class codes, their levels of assessment, and descriptions can be found on the Assessor's website (https://prodassets.cookcountyassessor.com/s3fs-public/form_documents/classcode.pdf). Note that class codes details can change across time. • The Change Reason and No Change Reason fields are only populated starting with the 2015 year data.

All data provided here is prepared for internal purposes by the County of Cook only is provided to the public as a courtesy.

While efforts have been made to be as accurate as possible, Cook County provides the data for personal use “as is”. The data is not guaranteed to be accurate, correct, or complete. Information provided should not be used as a substitute for legal, business, tax, or other professional advice. The recipient/viewer should contact appropriate regulating agencies to determine accuracy or suitability of the data for a particular use. This data may not be used in states that do not allow the exclusion or limitation of incidental or consequential damages.

Cook County or its staff assume no liability whatsoever for any losses that might occur from the use, misuse, or inability to use its geospatial data, maps or websites. All materials appearing on a map, geospatial data or County web site are transmitted without warranty of any kind and are subject to the terms on this disclaimer.

description: KML file of hospitals located in Cook County. To view or use these files, special GIS software such as Google Earth is required.; abstract: KML file of hospitals located in Cook County. To view or use these files, special GIS software such as Google Earth is required.

4-Band aerial imagery flown in 2021 for Cook County at 6 inch pixel resolution. Mosaic name is Cook2021. Service published on 8/9/2021.It is recommended that the GeoService URL is used for GIS applications, rather than downloading data.