About Property Index Number (PIN)

A PIN (Property Index Number, also known as a permanent real estate index number) is a numerical code for the legal description of a piece of land as it has been defined for the purposes of real estate taxation. The formatted code points to the parcel's location on the county's tax maps.


How to find your PIN

The best source for your PIN is your deed or tax bill, or other documents you may have from the purchase of your home. If you are not able to locate any of these documents, the Cook County Assessor's website can help you locate a PIN from an address.

Matches are not guaranteed, and there may be some addresses that are not available. In most cases the Assessor's office provides a photograph of the property, which can help verify the match of the address to the PIN.

Verify the PIN with the legal description on your deed to confirm you have identified the correct property. If you need assistance with reading the legal description*, please visit the Real Estate and Tax Services Division on the 4th floor of the Cook County Building, 118 N. Clark Street, Chicago, Illinois. We can assist you with examining official county tax maps.

How to read a PIN

The PIN is a 14-digit number composed of a 10-digit base that is modified for condominiums and leaseholds by adding a four-digit unit suffix. The basic PIN structure is:

  • AA is the AREA number (sequential township)
  • SS is the SUBAREA number (section)
  • BBB is the BLOCK number
  • PPP is the PARCEL number
  • UUUU is the UNIT number for condominiums and leaseholds (zeros in this portion of the PIN indicate non-condo and non-leasehold PINs)

This system uniquely identifies each tax parcel in Cook County and makes it possible for tax map users to quickly locate a parcel on a tax map.


    PIN = 12-26-328-009-0000

(click images for larger versions)

  • Use the two-digit area number (12 in the sample) to identify your township on the Cook County map.
  • Look within the township area identified in Step 1 to find your two-digit section number (26 in the sample).
  • Look within the subsection identified in Step 2 and use the three-digit block number (328 in the sample) to find your block.
Cook County AREA (AA) Numbering SUBAREAs (SS)
Within an Area
BLOCK ranges
in a Subarea
STEP 4: Look within your block identified in Step 3 to find your three-digit parcel number (009 in the sample). If the property in question is a condo or leasehold, the next four-digit number will identify the specific unit in a condo or the leaseholder. If this section contains zeros (as in the sample) the property is not a condo or leasehold.


Need more help?

Go to Tax FAQs and Glossary of Tax Terms