COOK COUNTY PROPERTY TAX APPEALS
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2026 DEADLINE TRACKER · VERIFIED SEPTEMBER 14, 2026
2026 Cook County property tax appeal deadlines
As of September 14, 2026, Cook County Assessor appeals are open in Barrington through September 23, Bremen through September 24, Lemont through September 29, Calumet through October 2, Hyde Park through October 8, Leyden through October 14, Worth through October 15, and Wheeling through October 22. The Board of Review is also open for Berwyn, Cicero, Elk Grove, Lakeview, Maine, and Palos through September 29.
Deadlines can change. Confirm the date for your property before filing; this tracker is informational and is not legal advice.
QUICK ANSWERS
What are the 2026 Cook County property tax appeal deadlines?
As of September 14, 2026, Cook County Assessor appeals are open in Barrington through September 23, Bremen through September 24, Lemont through September 29, Calumet through October 2, Hyde Park through October 8, Leyden through October 14, Worth through October 15, and Wheeling through October 22. The Board of Review is also open for Berwyn, Cicero, Elk Grove, Lakeview, Maine, and Palos through September 29.
How do I know which deadline applies to my property?
The controlling window is usually tied to the county and township where the property is assessed. Confirm the township using the property PIN, then use the official source linked on the matching record below.
What happens if my township’s deadline recently closed?
You generally cannot use a filing window after it closes. A later Board of Review window or another remedy may be available, but eligibility and timing differ by county and property, so confirm the next official deadline promptly.
Will a successful appeal lower my property tax bill?
An appeal challenges the property’s assessed value, not the bill directly. A lower assessment can reduce the resulting tax bill, but the final amount also depends on tax rates, exemptions, and other factors.
What evidence should I gather before filing?
Residential appeals commonly use comparable sales, comparable assessments, and property-record corrections. Commercial appeals may also require income and expense statements, rent rolls, vacancy evidence, or an appraisal.
2026 DEADLINE STATUS
Find the deadline that applies to your property
Cook County uses separate Assessor and Board of Review calendars. Start with Open now, then review Opening soon, Recently closed, and Dates pending. Every record identifies the appeal body and links to its official source.
Which townships are open for property tax appeals right now?
Fourteen verified Cook County filing windows are open as of September 14. Barrington closes first on September 23; six Board of Review windows and Lemont close September 29, followed by Assessor windows through October 22.
COOK COUNTY
OPEN
Barrington Township
The 2026 Cook County Assessor filing window is open through September 23.
COOK COUNTY
OPEN
Bremen Township
The 2026 Cook County Assessor filing window is open through September 24.
COOK COUNTY
OPEN
Palos Township — Board of Review
Board of Review Group 2 opened August 31, 2026, and closes September 29, 2026.
COOK COUNTY
OPEN
Maine Township — Board of Review
Board of Review Group 2 opened August 31, 2026, and closes September 29, 2026.
COOK COUNTY
OPEN
Lakeview Township — Board of Review
Board of Review Group 2 opened August 31, 2026, and closes September 29, 2026.
COOK COUNTY
OPEN
Elk Grove Township — Board of Review
Board of Review Group 2 opened August 31, 2026, and closes September 29, 2026.
COOK COUNTY
OPEN
Cicero Township — Board of Review
Board of Review Group 2 opened August 31, 2026, and closes September 29, 2026.
COOK COUNTY
OPEN
Berwyn Township — Board of Review
Board of Review Group 2 opened August 31, 2026, and closes September 29, 2026.
COOK COUNTY
OPEN
Lemont Township
The 2026 Cook County Assessor filing window is open through September 29, 2026.
COOK COUNTY
OPEN
Calumet Township
The 2026 Cook County Assessor filing window is open through October 2, 2026.
COOK COUNTY
OPEN
Hyde Park Township
The Assessor opened Hyde Park Township on August 26, 2026, with a last file date of October 8, 2026.
COOK COUNTY
OPEN
Leyden Township
Assessor appeal window opened August 31 and closes October 14, 2026. This is separate from the Board of Review calendar.
COOK COUNTY
OPEN
Worth Township
Assessor appeal window opened September 1 and closes October 15, 2026. This is separate from the Board of Review calendar.
COOK COUNTY
OPEN
Wheeling Township
Assessor appeal window opened September 9 and closes October 22, 2026. Wheeling is outside the 2026 triennial reassessment group, but the township is open for appeals. This is separate from the Board of Review calendar.
Which property tax appeal deadlines are opening soon?
No additional dated Cook County windows are currently announced beyond the open records below. Unpublished Assessor or Board of Review dates remain in Dates pending until an official Cook County source confirms them.
Which Cook County filing windows recently closed?
Northfield closed at the Assessor on September 4 and Lyons closed September 3. West Chicago closed August 21. These Assessor closures do not determine a separate Board of Review window, which must be checked on the Board’s official calendar.
Recently closed
Northfield Township
Cook County Assessor filing window closed September 4, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Lyons Township
Cook County Assessor filing window closed September 3, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
West Chicago Township
The 2026 Cook County Assessor filing window closed August 21, 2026. Check the official calendar and any available Board of Review options before acting.
Recently closed
Stickney Township
The 2026 Cook County Assessor filing deadline was August 12. Check the official calendar for any later review stage.
Recently closed
Elk Grove Township
The 2026 Cook County Assessor filing deadline was August 4. Check the official calendar for any later review stage.
Recently closed
Cicero Township
The 2026 Cook County Assessor filing deadline was July 31. Check the official calendar for any later review stage.
Recently closed
Maine Township
The 2026 Cook County Assessor filing deadline was July 21. Check the official calendar for any later review stage.
Recently closed
Palos Township
The 2026 Cook County Assessor filing deadline was July 17. Check the official calendar for any later review stage.
Recently closed
Lakeview Township
The 2026 Cook County Assessor filing deadline was July 13. Check the official calendar for any later review stage.
Which county has not announced all 2026 appeal dates?
No Cook County township dates are currently pending. This section is used only when the Cook County Assessor has not yet announced a filing window.
WHAT TO DO NEXT
A deadline is only the first decision
Before filing, compare the assessed value with recent sales, review the property record for errors, and decide whether comparable properties support an equity argument. Commercial appeals may also require income, expense, rent-roll, appraisal, or vacancy evidence.
Think your property is over-assessed?
Younis Law Group handles residential and commercial property tax appeals throughout Cook County.