Property tax appeal deadline in Cook County, Illinois

Typically 30 days after you receive your reassessment notice. The last date to file is printed on your notice.Appeal deadline

The details

How to appeal: File online with the Assessor. Filing is free. Paper forms are available if you cannot file online.¹
Who hears the appeal: The Cook County Assessor's Office first, then the Cook County Board of Review.¹²
If you lose: The Board of Review site lists the Property Tax Appeal Board (PTAB).²

The sources we read do not say: form, evidence to bring.

Illinois deadlines are set county by county. Cook County Board of Review dates run by township on its own schedule.

Many deadlines count from the date your assessment notice was mailed. Check the date on your notice.

Appeals, Cook County Assessor's Office, checked 1 November 2026
Cook County Board of Review, Cook County Board of Review, checked 1 November 2026

Checked 1 November 2026. "Secondary" marks a source used only because the official page could not be read.