Markham property tax appeals: deadlines and a free assessment check

Is your Markham home assessed higher than similar homes nearby? Check in a minute, then file yourself for free.

Free. No sign-up. Compares your home with the 5 to 10 most similar homes nearby, from the Assessor's own data.

Markham spans 2 townships. Your result page shows which one your home is in, and its exact deadline.

Bremen Township 73% of Markham's homes

The Assessor window has closed. The Board of Review opens this township later; check the Board's dates page or pre-register on its portal.

Cook County Assessor notices mailed August 12, 2026; appeals due September 24, 2026. File at the Assessor
Board of Review opens November 9, 2026; closes December 8, 2026. File at the Board

Last year 2,183 Bremen Township homeowners filed their own Board of Review appeal and 45% won a reduction.

Assessor appeals are open until November 23, 2026. 17 days left

Cook County Assessor notices mailed October 8, 2026; appeals due November 23, 2026. File at the Assessor
Board of Review dates not announced yet. Leave your email on your result page and we'll tell you when they are. File at the Board

Last year 4,475 Thornton Township homeowners filed their own Board of Review appeal and 46% won a reduction.

Run the free check above. It compares your assessed value per square foot with similar homes in your assessment neighborhood.
If yours looks high, get the evidence kit from the result page: the comps in the Board's format, recent sales, and a statement to paste into the form.
File online at the office whose window is open. Filing is free at both. You type the complaint yourself; only you or an Illinois attorney can file for your home.
Leave an email on the result page and we'll remind you a week and three days before the deadline.