Assessor - Parcel Addresses

Situs and mailing addresses of Cook County parcels. Used by the Assessor's office to mail assessment notices. This dataset was updated in March 2026 to include both owner <i>and</i> taxpayer information. Please note that owner name and mailing address is, to our knowledge, only intermittently updated in the ias source data. Users can use <a href="https://datacatalog.cookcountyil.gov/Property-Taxation/Assessor-Parcel-Sales/wvhk-k5uv/about_data">Parcel Sales data</a> to query owner and seller names. 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: <ul><li>Newer properties may be missing a mailing or property address, as they need to be assigned one by the postal service.</li> <li>Rowcount for a given year is final once the Assessor <a href="https://www.cookcountyassessor.com/assessment-calendar-and-deadlines">has certified the assessment roll</a> all townships.</li> <li>Data will be updated monthly.</li></ul>For more information on the sourcing of attached data and the preparation of this dataset, see the <a href="https://github.com/ccao-data/wiki/blob/master/SOPs/Open-Data.md">Assessor's Standard Operating Procedures for Open Data</a> on GitHub. <a href="https://datacatalog.cookcountyil.gov/stories/s/gzdr-q7c4">Read about the Assessor's 2025 Open Data Refresh.</a>