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Assessor - Parcel Universe
A complete, historic universe of Cook County parcels with attached geographic, governmental, and spatial data. When working with Parcel Index Numbers (PINs) make sure to zero-... -
Assessor [Archived 05-11-2022] - Experimental Single Family Sales Comparables
A data set showing algorithmically determined sales comparables for single family properties in Lake Township -
Assessor [Archived 05-11-2022] - Residential COVID Adjustment Replication Data
In response to the 2020 COVID-19 pandemic and its anticipated effects on the residential real estate market, the Cook County Assessor will adjust residential assessments. This... -
Assessor - Parcel Sales
Parcel sales for real property in Cook County, from 1999 to present. The Assessor's Office uses this data in its modeling to estimate the fair market value of unsold properties.... -
Assessor - Neighborhood Boundaries
Neighborhood polygons used by the Cook County Assessor's Office for valuation and reporting. These neighborhoods are specific to the Assessor. They are intended to represent... -
Assessor [Archived 05-11-2022] - Residential Modeling Characteristics (Chicago)
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... -
Assessor [Archived 05-18-2022] - Assessment Appeals by Town and Class - 2010
Assessment Appeals by Town and Class from Tax Year 2010. -
Assessor [Archived 05-11-2022] - Cook County Property Assessments
Every assessed value in Cook County 2010 to 2020, and appeal indicators. Each PIN has three stages of assessments each year: CCAO Mailed, CCAO Certified, and Board of Review... -
Assessor - Permits
Historical permit data submitted by municipalities to the Cook County Assessor's Office. When working with Parcel Index Numbers (PINs) make sure to zero-pad them to 14 digits.... -
Assessor - 2022 Open Data Refresh
A brief outline of the changes users can expect from the Assessor's open data offerings. -
Assessor [Archived 05-18-2022] - Homeowner Exemptions, by Town Number/Townshi...
Homeowner Exceptions by Town Number/Township in Tax Year 2010. -
Assessor - Appeals
Land, building, and total assessed values, pre and post-appeal with the Cook County Assessor’s office, for all Cook County parcels, from 1999 to present. The Assessor's Office... -
Assessor [Archived 05-11-2022] - Sales
Real estate sales data used by the Cook County Assessor to estimate Fair Cash Values for the purpose of property taxation. Deeds that include multiple PIN numbers are excluded... -
Assessor - Single and Multi-Family Improvement Characteristics
Single and multi-family (less than 7 units) property characteristics collected and maintained by the Assessor's Office for all of Cook County, from 1999 to present. The office... -
Assessor [Archived 05-11-2022] - First Pass Values
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... -
Assessor [Archived 05-11-2022] - Residential Neighborhood Boundaries
Neighborhoods play an important role in residential property assessment. Single-family and residential multi-family property assessments are sensitive to neighborhood... -
Assessor - Residential Condominium Unit Characteristics
Residential condominium unit characteristics collected and maintained by the Assessor's office for all of Cook County, from 1999 to present. The office uses this data primarily...