Parcels with property tax-exempt status across all of Cook County per tax year, from Tax Year 2022 on, with geographic coordinates and addresses.

Properties of religious, charitable, and educational organizations, as well as units of federal, state and local governments, can be eligible for exemption from property taxes. The Illinois Department of Revenue (IDOR) ultimately grants qualified organizations with property tax exempt status, with additional administration by the Board of Review and/or Assessor. Learn more here, and see the Assessor's guidance for religious organizations here.

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:

• Parcel entroids are based on Cook County parcel shapefiles.


• Newer properties may be missing a mailing or property address, as they need to be assigned one by the postal service.


• Exempt status for parcels changes regularly depending on the use and owner of a given parcel. Please contact Assessor.Exempt@cookcountyil.gov if you need additional information about parcels excluded from this dataset.


• Data will be updated monthly.


• This dataset contains data for the current tax year, which may not yet be complete or final. Assessed values and property tax-exempt status 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.


• 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.

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.

Commercial valuation data collected and maintained by the Cook County Assessor's Office, from 2021 to present. The office uses this data primarily for valuation and reporting. This dataset consolidates the individual Excel workbooks available on the Assessor's website into a single shared format. Properties are valued using similar valuation methods within each modelgroup, per township, per year (in the year the township is reassessed). This dataset has been cleaned minimally, only enough to fit the source Excel workbooks together - because models are updated for each township in the year it is reassessed, users should expect inconsistencies within columns across time and townships.

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 property-level. Each 14-digit key PIN represents one commercial property. Commercial properties can and often do encompass multiple PINs. Additional notes:

• 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.


• Data will be updated yearly, once the Assessor has finished mailing first pass values. If users need more up-to-date information they can access it through the Assessor's website.


• The Assessor's Office reassesses roughly one third of the county (a triad) each year. For commercial valuations, this means each year of data only contain the triad that was reassessed that year. Which triads and their constituent townships have been reassessed recently as well the year of their reassessment can be found in the Assessor's assessment calendar.


• Commercial properties are calculated by first determining a property’s use (office, retail, apartments, industrial, etc.), then the property is grouped with similar or like-kind property types. Next, income generated by the property such as rent or incidental income streams like parking or advertising signage is examined. Next, market-level vacancy based on location and property type is examined. In addition, new construction that has not yet been leased is also considered. Finally, expenses such as property taxes, insurance, repair and maintenance costs, property management fees, and service expenditures for professional services are examined. Once a snapshot of a property’s income statement is captured based on market data, a standard valuation metric called a “capitalization rate” to convert income to value is applied.


• This data was used to produce initial valuations mailed to property owners. It does not incorporate any subsequent changes to a property’s class, characteristics, valuation, or assessed value from appeals.

Township codes can be found in the legend of this map.

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.

Cook County 10-digit parcels with attached distances to various spatial features.

When working with 10-digit Parcel Index Numbers (PINs) make sure to zero-pad them to 10 digits. Some datasets may lose leading zeros for PINs when downloaded. 10-digit PINs do not identify individual condominium units.

Additional notes:

• Centroids are based on Cook County parcel shapefiles.


• Older properties may be missing coordinates and thus also missing attached spatial data (usually they are missing a parcel boundary in the shapefile).


• Attached spatial data does NOT all go back to 2000. It is only available for more recent years, primarily those after 2012.


• 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 annually as new parcel shapefiles are made available.

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.

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