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 uses this data primarily for valuation and reporting.

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.

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.

This data is improvement-level - 'improvements' are individual buildings on a parcel. Each row in a given year corresponds to a building e.g. two rows for the same parcel in one year means a parcel has more than one building.

Data will be updated bi-weekly. Rowcount and characteristics for the current year are only final once the Assessor has certified the assessment roll for all townships.

Depending on the time of year, some third-party and internal data will be missing for the most recent year. Assessments mailed this year represent values from last year, so this isn't an issue. By the time the Data Department models values for this year, those data will have populated.

NOTE: The Assessor's Office has recently changed the way Home Improvement Exemptions (HIEs) are tracked in its data. HIEs "freeze" a property's characteristics for a period of time with the intention of encouraging owners to improve their property without fear of assessment increases.

Historically, the updated, "improved" characteristics were saved in a separate file. However, in more recent years, the improved characteristics are saved in the main characteristics file. As such, the records in this data set from before 2021 do NOT include HIE characteristic updates, while those after and including 2021 DO include those updates.

For more information on HIEs, see the Assessor's Data Department wiki.

For more information on how this data is used to estimate property values, see the Assessor's residential modeling code on GitHub.

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.

On October 11, 2017, the Cook County Board repealed the Sweetened Beverage Tax Ordinance, effective December 1, 2017. This dataset is historical and no longer maintained.

This list is not meant to be exhaustive. There may be other products that meet the definitions of beverages for medical use, therapeutic nutritional meal replacements and weight reduction meal replacements. The Department of Revenue in no way endorses any of the products listed herein. For more information on the Sweetened Beverage Tax please see https://www.cookcountyil.gov/service/sweetened-beverage-tax

The Independent Inspector General is authorized to issue public statements in two circumstances: When an investigation that exonerates an individual who is publicly known to have been under investigation, where the subject requests such a statement; and when an investigation concerns inefficient or wasteful management, as opposed to individual misconduct or illegality.

This is a Cook County Feature class of Unincorporated Zoning District Boundaries by parcel. This data is provided by the Cook County Dept. Of Building and Zoning and is maintained by the Cook County Zoning Board of Appeals.
Only unincorporated district boundaries are available, please contact specific municipalities for questions regarding incorporated municipal zoning districts.

The OIIG has issued the following proposed legislation.

The intake data presented in this data reflects the cases brought in for review. Each row represents a potential defendant in a case.
Please use this link for more instructions and data glossary:
https://www.cookcountystatesattorney.org/resources/how-read-data

Local Animal Shelters and Animal Control Agencies for Locating Lost Pet and Veterinary Emergency Hospitals around Cook County

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/

The disposition data presented in this data reflects the culmination of the fact-finding process that leads to the resolution of a case. Each row represents a charge that has been disposed of.

Please use this link for more instructions and data glossary:
https://www.cookcountystatesattorney.org/resources/how-read-data

Update 10/31/2023: Sales are no longer filtered out of this data set based on deed type, sale price, or recency of sale for a given PIN with the same price. If users wish to recreate the former filtering schema they should set sale_filter_same_sale_within_365, sale_filter_less_than_10k, and sale_filter_deed_type to False.

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.

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.

Sale document numbers correspond to those of the Cook County Clerk, and can be used on the Clerk's website to find more information about each sale.

NOTE: These sales are filtered, but likely include non-arms-length transactions - sales less than $10,000 along with quit claims, executor deeds, beneficial interests are excluded. While the Data Department will upload what it has access to monthly, sales are reported on a lag, with many records not populating until months after their official recording date.

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.