People ask for "the Cook County appeal deadline" as if there is one date. There is not. There are dozens, and they open and close on a rolling schedule.
Quick Answer
Cook County is divided into 38 townships, and appeal windows open township by township, at two different offices, on their own timelines. The Assessor opens and closes a window for your township, and later the Board of Review opens its own. Missing a countywide date is the wrong worry. Missing your township's specific window is the real one.
Why it works this way
The county reassesses in three groups that rotate, and within each year the offices process townships in turn rather than all at once.
- The Assessor opens an appeal window for your township, then closes it and moves on.
- The Board of Review opens its own window for your township afterward.
- The two windows are separate, and a closed Assessor window does not mean the Board window is closed too.
So at any given moment, your township might be open at one office, closed at the other, or not yet open at either.
The triennial layer on top
Each property is reassessed once every three years. The three groups are the City of Chicago, the northern and northwest suburbs, and the southern and western suburbs. For 2026, the southern and western suburbs are the reassessment group.
That cycle changes the stakes of a given year, but not your right to appeal. You can appeal in non-reassessment years too, which is why missing one window is rarely the end of the road.
How to not miss it
- Find your township by name, not just your city.
- Check the Assessor's window for your township and the Board of Review's window separately.
- Treat every published date as something to confirm on the official calendar, because dates shift.
- Use the time before your window opens to gather evidence, so you are ready on day one.
Why a tracker helps
Because the schedule is rolling and split across two offices, a calendar that watches your specific township is more useful than any single date you write down. The deadline that matters is yours, and it has a habit of arriving while you are watching the wrong one.
Next step
There is no countywide deadline to circle. There is your township, at two offices, on a moving schedule.
Censum tracks township-level appeal windows so homeowners know when their specific window opens before they file, hire help, or give up a percentage of the result. Censum is independent and is not affiliated with Cook County or any government agency.