This repository contains two lists of PINs, or property index numbers, property class descriptions, and township GIS data. It will eventually contain property taxes data (billed and assessed values for all properties).
- All Cook County Property Index Numbers billed for 2014 and for 2016 (two separate lists)
- Other PINs we know about that aren't in list #1
A PIN describes a property, often in the form of a discrete parcel of a land, but frequently as a condo in a shared piece of land. Most of the PINs represent taxable properties; the remainder represent exempt properties, or "retired" PINs that resulted from splitting or joining PINned properties.
A PIN is 14 digits long and can be divvied into five, meaningful parts. A PIN is most often an integer, but many have leading zeros.
List 1 contains the response to a FOIA request [1], asking for a list of "all PINs" (and its metadata: property address, city, class, and description) that were on the tax roll in 2014, and we asked again for those in 2016.
- 1,864,384 PINs were received in the FOIA request (2014)
- 1,863,813 unique PINs (2014)
- 1,747,785 PINs were received in the FOIA request (2016)
- Download a list of PINs from 2014 (just the PIN)
- Download a list of PINs from 2016
- Download a list of PINs from 2021
List 2 contains 155,746 PINs that are in the Parcel2012 shapefile from the Cook County data portal but which are not present in List 1 ("all PINs").
149,750 is the number of PINS that had records on the Cook County Property Info Portal.
- Download a list of 155,746 PINs (just the PIN)
- Download PIN data (PIN and metadata)
When you're analyzing PINs and property taxes it's useful to know the property's class and class description. There are 132 unique classes, including null and "unclassified" values. The most common property class is "2-99, Residential condominium".
Townships are tax collecting boundaries and the sub-township neighborhood helps the township assessor asses a property's value.
This data is a manually-drawn GIS boundary of all of the townships and township neighborhoods within the City of Chicago. Drawing the boundary edges was based on Cook County assessor maps (like this one for Lake Township, neighborhood 30) and was assisted by the street center lines and other official boundary data. Drawn by Yonah Freemark.
- Download as a zipped shapefile. Projection is EPSG:3435, Illinois StatePlane East (feet)
- Download as GeoJSON. Projection is EPSG:4326, WGS84 mercator
[1] The FOIA request to the Cook County Treasurer's office was considered voluminous and would cost money; the original response said that 50 PINs would fit on a page, making for over 36,000 pages. We inquired about the possibility of providing it in an Excel spreadsheet. The final request was returned in 11 Excel documents after transmitting $100. It was noted in the FOIA request that it was for a commercial use – this extends the time the office has to respond from 5 days to 25 days.