Cook County property tax
appeal deadlines.
The 11 townships with a published 2026 filing deadline, straight from the Cook County Assessor's calendar. The rest are marked pending until the Assessor posts them — we don't guess. Always confirm your exact deadline with the county before filing.
Verify your deadline before you file.
Dates shown here are an indicative planning guide, not an official deadline. Cook County publishes and revises appeal dates throughout the year, and they vary by township. Always confirm your exact filing deadline with the official county source below before you file.
- Cook County Assessor — Assessment & Appeal CalendarThe official filing deadline (last file date) for each township. Updated through the year as townships open.
- Cook County Board of Review — AppealsThe second-level appeal window, which opens separately from the Assessor's and has its own deadline per township.
- Cook County Assessor — Property SearchLook up your PIN, township, and current assessment by address.
Not sure which window applies to you? Request a review and we'll help you confirm it — email support@overtaxed-il.com or call (847) 461-3189. We never file anything without your go-ahead.
Get a reminder when your township's official deadline is posted.
We'll email you when the Assessor publishes your township's 2026 deadline and again before it closes. Nothing else.
Township deadlines at a glance.
Grouped by the Assessor's official 2026 status. “Pending official date” means the county hasn't posted that township yet — confirm yours before filing.
- BloomPending official date
- BremenPending official date
- CalumetPending official date
- CiceroPending official date
- LemontPending official date
- LyonsPending official date
- OrlandPending official date
- ProvisoPending official date
- RichPending official date
- StickneyPending official date
- ThorntonPending official date
- WorthPending official date
- BarringtonPending official date
- Elk GrovePending official date
- HanoverPending official date
- LeydenPending official date
- NilesPending official date
- NorthfieldPending official date
- PalatinePending official date
- SchaumburgPending official date
- WheelingPending official date
- Hyde ParkPending official date
- JeffersonPending official date
- LakePending official date
- North ChicagoPending official date
- South ChicagoPending official date
- West ChicagoPending official date
Official 2026 township deadlines.
Dates shown are the Cook County Assessor's official 2026 Last File Date. Townships marked “Pending official date” have not been posted yet — we don't estimate them. Confirm any date on the official Cook County Assessor calendar before filing.
| Township | Status | Official 2026 deadline | Days | Cycle | |
|---|---|---|---|---|---|
| Oak Park | Open | Last file: June 18, 2026 | 1 day left | 2026 | → |
| New Trier | Open | Last file: June 22, 2026 | 5 days left | 2027 | → |
| Berwyn | Open | Last file: July 6, 2026 | 19 days left | 2026 | → |
| Lake View | Open | Last file: July 13, 2026 | 26 days left | 2028 | → |
| Palos | Open | Last file: July 17, 2026 | 30 days left | 2026 | → |
| Maine | Open | Last file: July 21, 2026 | 34 days left | 2027 | → |
| Norwood Park | Closed | Last file: May 26, 2026 | deadline passed | 2027 | → |
| Rogers Park | Closed | Last file: June 1, 2026 | deadline passed | 2028 | → |
| River Forest | Closed | Last file: June 2, 2026 | deadline passed | 2026 | → |
| Evanston | Closed | Last file: June 4, 2026 | deadline passed | 2027 | → |
| Riverside | Closed | Last file: June 8, 2026 | deadline passed | 2026 | → |
| Barrington | Pending date | Pending official date | — | 2027 | → |
| Bloom | Pending date | Pending official date | — | 2026 | → |
| Bremen | Pending date | Pending official date | — | 2026 | → |
| Calumet | Pending date | Pending official date | — | 2026 | → |
| Cicero | Pending date | Pending official date | — | 2026 | → |
| Elk Grove | Pending date | Pending official date | — | 2027 | → |
| Hanover | Pending date | Pending official date | — | 2027 | → |
| Hyde Park | Pending date | Pending official date | — | 2028 | → |
| Jefferson | Pending date | Pending official date | — | 2028 | → |
| Lake | Pending date | Pending official date | — | 2028 | → |
| Lemont | Pending date | Pending official date | — | 2026 | → |
| Leyden | Pending date | Pending official date | — | 2027 | → |
| Lyons | Pending date | Pending official date | — | 2026 | → |
| Niles | Pending date | Pending official date | — | 2027 | → |
| North Chicago | Pending date | Pending official date | — | 2028 | → |
| Northfield | Pending date | Pending official date | — | 2027 | → |
| Orland | Pending date | Pending official date | — | 2026 | → |
| Palatine | Pending date | Pending official date | — | 2027 | → |
| Proviso | Pending date | Pending official date | — | 2026 | → |
| Rich | Pending date | Pending official date | — | 2026 | → |
| Schaumburg | Pending date | Pending official date | — | 2027 | → |
| South Chicago | Pending date | Pending official date | — | 2028 | → |
| Stickney | Pending date | Pending official date | — | 2026 | → |
| Thornton | Pending date | Pending official date | — | 2026 | → |
| West Chicago | Pending date | Pending official date | — | 2028 | → |
| Wheeling | Pending date | Pending official date | — | 2027 | → |
| Worth | Pending date | Pending official date | — | 2026 | → |
Check if your assessment is too high.
Knowing the deadline is half of it. The other half is knowing whether your assessed value is actually out of line with comparable properties. Free, takes 30 seconds, no signup.