This is the data set of residential sales used by the Cook County Assessor in their Computer Assisted Mass Appraisal system used to assess residential property values. This data set contains property information for every arm's-length residential sale in Cook County where class is within a specified list of classes. For disclaimers, see data set narrative at https://datacatalog.cookcountyil.gov/stories/s/p2kt-hk36 This data set was replaced by the more comprehensive data set Cook County Assessor's Sales.

This data contains every residential Property Index Number (PIN) and corresponding Assessed Values from significant stages in the assessment process. This data was replaced with the more comprehensive Cook County Assessor's Fair Cash Values.

Assessment dataset used by the Cook County Assessor in their Computer Assisted Mass Appraisal (CAMA) system used to assess residential properties in Northern Triennial Townships. This dataset contains property information for every residential PIN in the northern triennial townships where class is within a specified list of classes. For disclaimers, see dataset narrative at https://datacatalog.cookcountyil.gov/stories/s/p2kt-hk36

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 model group, 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:

This data set contains characteristic data points used by the Cook County Assessor in the 2021 Chicago reassessment to produce initial estimates of the current market value of most Chicago homes (single-family homes, small multi-family homes, and condo units). You can use the "Filter" option to search for a property's PIN or address, and see what data the Assessor’s Office had about a home’s characteristics at the time of modeling*. To learn more about how the 2021 model used this data, read about our public Residential Automated Valuation Model here. Chicago properties not listed here are reassessed using different modeling procedures. *Important Note: This dataset is, at the time of publication, an early snapshot of data. Data about a home might change later in the assessment process this year as Assessor’s Office staff and analysts review these properties. After this review, updated characteristics and market values are mailed to homeowners. If the data listed on the assessment notice is incorrect, an appeal can be filed to provide the correct characteristics.

As of February 14, 2020 this dataset will be considered archived information and will no longer be updated. First-pass property values as assessed by the Cook County Assessor in their Computer Assisted Mass Appraisal system used to assess residential properties. This dataset contains first pass values for 2019 and corresponds with residential PINs in the Cook County Assessor's Assessment Data. These are NOT final assessed values. For Disclaimers, see dataset narrative at https://datacatalog.cookcountyil.gov/stories/s/p2kt-hk36

A data set showing algorithmically determined sales comparables for single family properties in Lake Township

Homeowner Exceptions by Town Number/Township in Tax Year 2010.

Assessment Appeals by Town and Class from Tax Year 2010.

This data represents all of the County’s residential real estate properties and all of the associated tax charges and credits with that property processed at the annual billing in July of each year, excluding any subsequent billing additions and/or revisions throughout the year. This dataset excludes the names of the property owners. The addresses in this database represent the address of the property. For more information about the individual taxes and credits, please go to http://www.montgomerycountymd.gov/finance/taxes/faqs.html#credit. Update Frequency: Updated Annually in July