The update script for this dataset is currently broken. Please see the Cook County Clerk SEI Search for recent filings. For extended information about Statements of Economic Interests in Cook County IL, visit the Cook County Clerk's SEI search: http://ethics.cookcountyclerk.com/PublicSearch/

This dataset provides a cumulative record of payment and invoice details for County suppliers, vendors and other payees. Data is from December 1, 2016 to present. Payment data prior to December 1, 2016 is archived in the Cook County Check Register here: https://datacatalog.cookcountyil.gov/Finance-Administration/Cook-County-Check-Register/gywr-fjeh

Historic land, building, and total assessed values for all Cook County parcels, from 1999 to present. The Assessor's Office uses these values for reporting, evaluating assessment performance over time, and research.

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.

This data is parcel-level. Each row contains the assessed values for a single PIN for a single year. Important notes:

• Assessed values are available in three stages: 1) mailed, these are the initial values estimated by the Assessor's Office and mailed to taxpayers. 2) certified, these are values after the Assessor's Office closes appeals. 3) Board of Review certified, these are values after the Board of Review closes appeals.


• The values in this data are assessed values, NOT market values. Assessed values must be adjusted by their level of assessment to arrive at market value. Note that levels of assessment have changed throughout the time period covered by this data set.


• This data set will be updated roughly contemporaneously (monthly) with the Assessor's website as values are mailed and certified. However, note that there may be small discrepancies between the Assessor's site and this data set, as each pulls from a slightly different system. If you find a discrepancy, please email the Data Department using the contact link below.


• This data set contains data for the current tax year, which may not be complete or final. PINs can still be added and removed to the universe and values can change up until the Board of Review closes appeals.


• Rowcount and characteristics for a given year are final once the Assessor has certified the assessment roll for all townships. Values should be considered final once the Board of Review closes its appeals, though there are a few rare circumstances where values may change for the current or past years after that.


• Current property class codes, their levels of assessment, and descriptions can be found on the Assessor's website. Note that class codes details can change across time.

Read about the Assessor's 2022 Open Data Refresh.

2012 budget request detail.

Scavenger Tax Sale: A sale held every two years by the Treasurer selling taxes on property with 2 or more years of delinquent taxes.

A brief outline of the changes users can expect from the Assessor's open data offerings.

Cook County GIS Department map of Cook County Commissioner Districts in PDF format. Includes major streets, waterbodies, rail, and Cook County Commissioner District boundaries.

Assessment Appeals by Town and Class from Tax Year 2010.

¹ Includes Sales Tax previously allocated to JTDC for FY08--9. Reflects rate reduction for last 2 months of FY10, last 8 months of FY12 and FY13
² Provided for comparison purposes to revenues as shown in Revenue Estimate
³ Sources: FY07-FY11 from Budget Citizen's Summary, Q-1 Total General Fund Expenditures. FY13-16 based on FY12 with 3.2% annual growth (10 year CPI-U-2.44%/Health-8%).