Every dataset we use, and who publishes it
Phase 1 covers the Property domain in Cook County and Chicago. Sources for Health & Care and Hiring & Education will be listed here as each report is built.
Ten official datasets, 26,491,870 records
Counts are the rows each publisher reported for the years we keep, verified on 13 Sep 2026. None is fully loaded yet.
Scroll the table sideways for refresh, terms and use.
| Dataset | Publisher | Dataset ID | Years kept | Records | Refresh | Terms | Used by |
|---|---|---|---|---|---|---|---|
| Parcel universe (current year) | Cook County Assessor | pabr-t5kh | 2026 | 1,863,665 | Monthly | Pending | Tax Appeal, Permits |
| Parcel addresses | Cook County Assessor | 3723-97qp | 2025–2026 | 3,727,473 | Monthly | Pending | Tax Appeal, Permits |
| Assessed values | Cook County Assessor | uzyt-m557 | 2023–2026 | 7,455,734 | Weekly | Pending | Tax Appeal |
| Residential characteristics | Cook County Assessor | x54s-btds | 2023–2026 | 4,409,607 | Monthly | Pending | Tax Appeal, Permits |
| Condominium characteristics | Cook County Assessor | 3r7i-mrz4 | 2023–2026 | 1,829,213 | Monthly | Pending | Tax Appeal |
| Parcel sales | Cook County Assessor | wvhk-k5uv | 2015–2026 | 1,210,856 | Monthly | Pending | Tax Appeal |
| Assessor appeals | Cook County Assessor | y282-6ig3 | 2023–2026 | 1,150,106 | Monthly | Pending | Tax Appeal |
| Appeal decision history | Cook County Board of Review | 7pny-nedm | 2022–2025 | 1,970,286 | Every 2 months | Pending | Tax Appeal |
| Building permits | City of Chicago | ydr8-5enu | All | 847,122 | Daily | Pending | Permits |
| Building violations | City of Chicago | 22u3-xenr | All | 2,027,808 | Daily | Pending | Permits |
| Total, 10 datasets | 26,491,870 | ||||||
“Pending” terms: the publisher’s terms of use haven’t yet been reviewed by a person. That review is required before any paid use.
City of Chicago data notice
This site provides applications using data that has been modified for use from its original source, www.cityofchicago.org, the official website of the City of Chicago. The City of Chicago makes no claims as to the content, accuracy, timeliness, or completeness of any of the data provided at this site. The data provided at this site is subject to change at any time. It is understood that the data provided at this site is being used at one’s own risk.
Cook County data notice
Cook County data is provided by Cook County on an “as is” basis. Cook County does not endorse CivicDelta or any report built from its data, and CivicDelta is not affiliated with Cook County, the Cook County Assessor’s Office or the Board of Review.