Situs and mailing addresses of Cook County parcels. Used by the Assessor's office to mail assessment notices.

As of 2017 mailing addresses in this dataset are no longer being regularly updated. We are trying to figure out a solution to this problem.

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Additional notes: Mailing addresses can be out of date or fail to properly reflect deed transfers. 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.For more information on the sourcing of attached data and the preparation of this dataset, see the Assessor's Standard Operating Procedures for Open Data on GitHub.

Read about the Assessor's 2025 Open Data Refresh.