Cook County Parcel Universe with Tax and Geographic Attributes

Parcel records for Cook County, Illinois, include geographic, governmental, and spatial data attached to each property. The dataset is maintained by the Cook County Assessor's Office and is updated monthly, containing data for the current tax year. It serves as a historic universe of property information, linking parcels to taxing districts and spatial features.

Use Cases

• Analyzing property tax burdens by linking parcels to specific tax districts like school_unified_district_name and tax_municipality_name.
• Mapping parcel locations and associated spatial attributes using centroid coordinates and neighborhood_code.
• Studying the impact of special zones on property values using columns like qualified_opportunity_zone_num and industrial_growth_zone_data_year.
• Assessing environmental or noise impacts on properties via airport_noise_dnl and ohare_noise_contour_half_mile_buffer_bool.

Strengths

• Cross-platform presence on Socrata and Data.gov signals its importance and reliability as a core government dataset.
• Monthly updates ensure the data reflects the current tax year's status, though values may be provisional.
• Attaches a wide range of geographic and governmental data via spatial joins and tax code assignments.

Limitations

• Row count, size, license, and author information are unknown or conflicting across sources.
• Older properties may lack coordinates, and newer properties may be missing mailing addresses, leading to incomplete spatial joins.
• Assessed values for the current year are subject to change until certified by the Cook County Board of Review.

Provenance

Source

Cook County Assessor's Office

Collection Method

Data is compiled from parcel shapefiles and attached to taxing district data via spatial joins (st_contains) and tax code assignments.

Time Range

Historic universe with data for the current tax year; specific start date unknown.

Freshness

Most recent update was 2026-04-05 according to two sources, indicating active maintenance.

Geography

Cook County, Illinois, USA.