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-pad them to 14 digits. Some datasets may lose leading zeros for PINs when downloaded.

Additional notes:

• Data is attached via spatial join (st_contains) to each parcel's centroid.


• 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).


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


• Attached spatial data does NOT go all the way back to 1999. It is only available for more recent years, primarily those after 2012.


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


• Data will be updated monthly.


• Rowcount and characteristics for a given year are 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.


• 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.


• Due to decrepencies between the systems used by the Assessor and Clerk's offices, tax_district_code is not currently up-to-date in this table.

For more information on the sourcing of attached data and the preparation of this dataset, see the Assessor's data architecture repo on GitLab.

The Independent Inspector General submits Quarterly Reports to the MWRD Board of Commissioners and Executive Director. The Quarterly Report is released the 15th day of January, April, July, and October of each year. Quarterly Reports chronicle the number and type of investigations initiated, concluded or pending since the date of the last report and whether any recommendations for remedial action were made and whether or not the recommendations were followed by the MWRD.

This check register provides a cumulative record of payments to County suppliers, vendors and other payees as approved by the Cook County Board of Commissioners. Data covers December 2009 through November 2016. For data after November 2016 click here: https://datacatalog.cookcountyil.gov/Finance-Administration/Cook-County-Check-Register/4h27-5s9x

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

2012 budget requests by line-item, by bureau, and elected official.

The bid tabulations provided herein are preliminary and are for informational purposes only. The purpose of providing this preliminary information is to improve process transparency. The information contained in the preliminary bid tabulations is subject to change pending math review, analysis of all bids, and review of documentation provided.
Bids: All bids estimated at $25,000 or more are publicly opened and read at the time, date, and place specified in the bid document.
RFP/RFQ/RFI: Responses to RFP/RFQ/RFI are not publicly opened. Names of respondents will be made available based on the names identified on the sealed package and is, therefore, subject to change.

For bid tabulations before June 2016 see https://datacatalog.cookcountyil.gov/d/pn38-yupm

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-pad them to 14 digits. Some datasets may lose leading zeros for PINs when downloaded.

Additional notes:

• Non-taxing district data is attached via spatial join (st_contains) to each parcel's centroid.


• Tax district data (school district, park district, municipality, etc.) are attached by a parcel's assigned tax code.


• 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).


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


• 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 monthly.


• 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.


• 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.


• Due to decrepencies between the systems used by the Assessor and Clerk's offices, tax_district_code is not currently up-to-date in this table.

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.