Cook County Property Assessment Appeals from 1999 to Present

Parcel-level records of land, building, and total assessed values before and after appeals with the Cook County Assessor's Office, spanning from 1999 onward. The dataset includes currently open appeal cases, with data subject to change, and is updated monthly. Cook County of Illinois provides this data for reporting, evaluating assessment performance, and research.

Use Cases

• Tracking changes in assessed property values over time based on pre- and post-appeal data.
• Analyzing the volume and outcomes of property assessment appeals at the parcel level.
• Researching the impact of appeals on final certified property tax assessments.
• Comparing initial mailed assessments to final certified values for performance evaluation.

Strengths

• Monthly updates ensure relatively current data.
• Covers a long temporal range from 1999 to the present.
• Includes data for all parcels in Cook County, providing broad geographic coverage.

Limitations

• Appeal data is sparse prior to 2021, with missing records expected to be repopulated by the end of 2025.
• Columns and row counts are unknown, limiting suitability assessment.
• Data includes currently open appeal cases that are not final and subject to change.

Provenance

Source

Cook County Assessor's Office, Cook County of Illinois

Collection Method

Likely administrative records from the property tax assessment and appeals process.

Time Range

1999 to present

Freshness

Updated monthly; last metadata update was 2026-03-08.

Geography

Cook County, Illinois, USA