Guide · sources read Nov 9, 2026
How to read an Illinois parcel number
Illinois law lets a county set up a property index number (PIN) system that describes land by township, section, block and parcel or lot.1 Each county lays it out its own way: Cook County's PIN has 14 digits, DuPage County's 10.23
Also called the PIN (property index number).
County by county
Cook County
Example: 01-02-300-034-0000. On Groundwork: 01-02-300-034-00004.
| 01-02-300-034-0000 | What it means |
|---|---|
| 01 | area (the township) |
| 02 | subarea (the section) |
| 300 | block |
| 034 | parcel |
| 0000 | unit; all zeros when it is not a condominium or leasehold |
Read from the county's own layout2.
DuPage County
The DuPage County Clerk's Office assigns the PIN.3
Example: 10-11-203-005. On Groundwork: 10-11-203-0054.
| 10-11-203-005 | What it means |
|---|---|
| 10 | township |
| 11 | section |
| 203 | block |
| 005 | parcel |
Read from the county's own layout3.
Look up an Illinois parcel number
Type the number the way the county prints it. A county not shown here may lay its number out differently; its assessor's site has the layout.
Questions
What is a parcel number in Illinois?
Illinois law lets a county set up a property index number (PIN) system that describes land by township, section, block and parcel or lot. Each county lays it out its own way: Cook County's PIN has 14 digits, DuPage County's 10.
How do I look up an Illinois parcel number on Groundwork?
Type it in the map search the way the county prints it. Example from Cook County: 01-02-300-034-0000. Groundwork shows it as Parcel 01-02-300-034-0000.
Sources
- 35 ILCS 200/9-45, Property index number system (Illinois Property Tax Code). Read Nov 9, 2026.
- Cook County Clerk: About the Property Index Number (PIN). Read Nov 9, 2026.
- DuPage County Clerk: Tax History Search. Read Nov 9, 2026.
- Groundwork map search: each example on this page was searched and returned that parcel first. Checked Nov 9, 2026.