Cook County property assessments and appeals: how the calendar works

In Cook County a single office, the Cook County Assessor, values property for the whole county. That sets it apart from the rest of Illinois, where township assessors do the work.

The reassessment rotation

The Assessor reassesses the county region by region in turn: the City of Chicago, the north suburbs, and the south and west suburbs. In a region's reassessment year, values can change more than in the years between.

The appeals calendar

1. Assessor appeals. Each township has its own appeal window, opened after its assessment notices are mailed. Owners can appeal to the Assessor during that window.
2. Board of Review. After the Assessor's window, owners can appeal to the Cook County Board of Review, again during a window set for their township.
3. After that. An owner who still disagrees can go to the state Property Tax Appeal Board or to court.

Why it matters to buyers

A new assessment changes the tax bill a buyer will inherit, and the township calendar decides when it can still be challenged. Checking where a township is in the cycle is part of pricing any Cook County property.

Where the official records are

The Assessor publishes each township's notice and appeal dates and its assessed values; the Board of Review publishes its own township schedule and decisions.

See the Cook County page.

This guide explains the process in general terms. It isn't legal or tax advice.