How to file a Cook County Assessor appeal
The Assessor appeal is the first township-specific review opportunity. If that window is open, use it before moving on to the Board of Review so you do not give up a separate chance to reduce the assessment.
Check your assessment against similar Cook County homes.
Enter a Cook County address or property PIN.
Free to check first. No credit card required.
When can you appeal?
Cook County opens Assessor appeals by township. In a reassessment year, the notice mailed to the owner includes the proposed value and filing deadline. Outside a reassessment year, owners may still appeal when their township opens.
The filing period is short, so verify the current township deadline before spending time building the case.
How Cook County appeal deadlines work → Already missed the Assessor deadline? See what can still be available →Three common reasons to appeal
What makes a useful uniformity case?
The Assessor's rules say comparable properties should be similar in size, class, characteristics, and location. At least three comparables are required for a comps-based filing, and the Assessor recommends at least five. The point is not to cherry-pick the lowest assessments; it is to show a coherent pattern among genuinely similar properties.
See the Cook County uniformity appeal guide →Where do you file?
The Assessor's electronic filing system is SmartFile. A homeowner can file without an attorney. Keep the confirmation and a copy of every document you submit.
What happens after the Assessor?
If you do not receive the reduction you want, the Board of Review is a separate second review opportunity. A Board pre-file does not replace an open Assessor appeal. Preserve the Assessor opportunity first when it is still available.
Board of Review appeal guide →See whether your assessment looks out of line before you file.
Deadlines and filing procedures can change. The official Cook County Assessor calendar and SmartFile system control.