COOK COUNTY PROPERTY TAX APPEALS
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2026 DEADLINE TRACKER · VERIFIED AUGUST 24, 2026
2026 Cook County property tax appeal deadlines
As of August 24, 2026, Cook County Assessor appeals are open in Lyons through September 3, Northfield through September 4, Barrington through September 23, Bremen through September 24, Lemont through September 29, and Calumet through October 2. West Chicago closed August 21. Other Cook County township windows will be added only when confirmed by an official source.
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 August 24, 2026, Cook County Assessor appeals are open in Lyons through September 3, Northfield through September 4, Barrington through September 23, Bremen through September 24, Lemont through September 29, and Calumet through October 2. West Chicago closed August 21. Other Cook County township windows will be added only when confirmed by an official source.
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
Township and county schedules differ. Start with Open now, then review Opening soon, Recently closed, and Dates pending. Every record links to the official county source.
Which townships are open for property tax appeals right now?
Seventeen verified filing windows are open as of August 24. Benton and Ela close today, followed by Lyons on September 3 and Northfield on September 4.
COOK COUNTY
OPEN
Lyons Township
The 2026 Cook County Assessor filing window is open through September 3.
COOK COUNTY
OPEN
Northfield Township
The 2026 Cook County Assessor filing window is open through September 4.
COOK COUNTY
OPEN
Barrington Township
The 2026 Cook County Assessor filing window is open through September 23.
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OPEN
Bremen Township
The 2026 Cook County Assessor filing window is open through September 24.
COOK COUNTY
OPEN
Lemont Township
The 2026 Cook County Assessor filing window is open through September 29, 2026.
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OPEN
Calumet Township
The 2026 Cook County Assessor filing window is open through October 2, 2026.
Which property tax appeal deadlines are opening soon?
No additional verified Cook County filing windows are scheduled to open after August 24. Unpublished dates remain in Dates pending until the Cook County Assessor announces them.
Which Cook County filing windows recently closed?
West Chicago closed August 21, following Stickney on August 12. Other recently closed Cook County Assessor windows appear below; check the official calendar for any later review stage.
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.