Cook County Property Tax Appeal Deadline
Deadline varies by county — check your county's appraisal district.
Key Dates for Cook County
| Appeal deadline | Appeals are filed in two separate, sequential stages, each opening township-by-township (board-session style), not on a single county-wide date. Stage 1 — the Cook County Assessor's Office opens each township for ~30 days following its reassessment/notice mailing (e.g., for the 2026 south/west suburban reassessment: River Forest closes 6/2/2026, Riverside 6/8/2026, Oak Park 6/18/2026, Berwyn 7/6/2026). Stage 2 — after the Assessor certifies a township, the Cook County Board of Review opens its own ~30-day appeal window for that township. The exact open/close dates change every year and must be checked on the Assessor's Assessment & Appeal Calendar and the Board of Review's Dates and Deadlines page. |
|---|---|
| Lien date | January 1, 2026 |
| Statute | 35 ILCS 200/16-55 (Board of Review complaints, counties under 3,000,000); 35 ILCS 200/16-160 (petition to PTAB) |