COOK COUNTY PROPERTY TAX APPEALS
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2026 DEADLINE TRACKER · VERIFIED OCTOBER 10, 2026
2026 Cook County property tax appeal deadlines
As of October 10, 2026, ten Cook County Assessor appeal windows are open. Leyden closes October 14 and Worth October 15; later deadlines run through November 23. Board of Review Group 3 is open for Lyons, Northfield, Stickney, and West Chicago through November 6, with evidence due November 16. Find your township below and confirm the date with the 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?
Cook County deadlines depend on your township and the appeal body. As of October 10, 2026, ten Assessor windows are open, with deadlines from October 14 through November 23. Board of Review Group 3 complaint filing is open for Lyons, Northfield, Stickney, and West Chicago through November 6; its separate evidence deadline is November 16. Check your township’s record below before filing.
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 October 10: ten at the Assessor and four at the Board of Review. Leyden closes first on October 14, followed by Worth on October 15. Board of Review Group 3 complaint filing closes November 6; evidence is due November 16.
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.
COOK COUNTY
OPEN
Proviso Township
Cook County Assessor 2026 reassessment township. The reassessment notice date is September 14 and the Assessor last file date is October 27. This is not a Board of Review deadline.
COOK COUNTY
OPEN
Lake Township (Cook County)
Cook County Lake Township in Chicago, not Lake County. The Assessor calendar lists September 16 as its notice/open date and October 29 as its last file date. This is not a Board of Review deadline.
COOK COUNTY
OPEN
Palatine Township
The Cook County Assessor appeal window opened September 22 and closes November 4, 2026. This is separate from any Board of Review complaint or evidence deadline.
COOK COUNTY
OPEN
Orland Township
The Cook County Assessor appeal window opened September 24 and closes November 6, 2026. This is separate from any Board of Review complaint or evidence deadline.
COOK COUNTY
OPEN
Lyons Township — Board of Review
Board of Review Group 3 opened for complaint filing October 8, 2026, and closes November 6, 2026. The separate evidence-submission deadline is November 16, 2026. This is not an Assessor deadline.
COOK COUNTY
OPEN
Northfield Township — Board of Review
Board of Review Group 3 opened for complaint filing October 8, 2026, and closes November 6, 2026. The separate evidence-submission deadline is November 16, 2026. This is not an Assessor deadline.
COOK COUNTY
OPEN
Stickney Township — Board of Review
Board of Review Group 3 opened for complaint filing October 8, 2026, and closes November 6, 2026. The separate evidence-submission deadline is November 16, 2026. This is not an Assessor deadline.
COOK COUNTY
OPEN
West Chicago Township — Board of Review
Board of Review Group 3 opened for complaint filing October 8, 2026, and closes November 6, 2026. The separate evidence-submission deadline is November 16, 2026. This is not an Assessor deadline.
COOK COUNTY
OPEN
Jefferson Township
The Cook County Assessor appeal window opened September 29 and closes November 12, 2026. This is separate from any Board of Review complaint or evidence deadline.
COOK COUNTY
OPEN
Schaumburg Township
The Cook County Assessor appeal window opened October 6 and closes November 19, 2026. This is separate from any Board of Review complaint or evidence deadline.
COOK COUNTY
OPEN
Thornton Township
The Cook County Assessor appeal window opened October 8 and closes November 23, 2026. This is separate from any Board of Review complaint or evidence deadline.
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?
Hyde Park’s Assessor filing window closed October 8; Calumet closed October 2, Lemont September 29, Bremen September 24, and Barrington September 23. Board of Review Group 2 complaint filing closed September 29 and its evidence deadline passed October 9. A closed Assessor window does not rule out a separate Board of Review window—check both calendars.
Recently closed
Hyde Park Township
The 2026 Cook County Assessor filing window closed October 8, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Calumet Township
The 2026 Cook County Assessor filing window closed October 2, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Palos Township — Board of Review
Board of Review Group 2 complaint filing closed September 29, 2026. The separate evidence-submission deadline was October 9, 2026. Both dates have passed; this is not an Assessor deadline.
Recently closed
Maine Township — Board of Review
Board of Review Group 2 complaint filing closed September 29, 2026. The separate evidence-submission deadline was October 9, 2026. Both dates have passed; this is not an Assessor deadline.
Recently closed
Lakeview Township — Board of Review
Board of Review Group 2 complaint filing closed September 29, 2026. The separate evidence-submission deadline was October 9, 2026. Both dates have passed; this is not an Assessor deadline.
Recently closed
Elk Grove Township — Board of Review
Board of Review Group 2 complaint filing closed September 29, 2026. The separate evidence-submission deadline was October 9, 2026. Both dates have passed; this is not an Assessor deadline.
Recently closed
Cicero Township — Board of Review
Board of Review Group 2 complaint filing closed September 29, 2026. The separate evidence-submission deadline was October 9, 2026. Both dates have passed; this is not an Assessor deadline.
Recently closed
Berwyn Township — Board of Review
Board of Review Group 2 complaint filing closed September 29, 2026. The separate evidence-submission deadline was October 9, 2026. Both dates have passed; this is not an Assessor deadline.
Recently closed
Lemont Township
The 2026 Cook County Assessor filing window closed September 29, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Bremen Township
The 2026 Cook County Assessor filing window closed September 24, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Barrington Township
The 2026 Cook County Assessor filing window closed September 23, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Northfield Township
The 2026 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
The 2026 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 separate Board of Review calendar for a later township window.
Recently closed
Stickney Township
The 2026 Cook County Assessor filing window closed August 12, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Elk Grove Township
The 2026 Cook County Assessor filing window closed August 4, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Cicero Township
The 2026 Cook County Assessor filing window closed July 31, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Maine Township
The 2026 Cook County Assessor filing window closed July 21, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Palos Township
The 2026 Cook County Assessor filing window closed July 17, 2026. Check the separate Board of Review calendar for a later township window.
Recently closed
Lakeview Township
The 2026 Cook County Assessor filing window closed July 13, 2026. Check the separate Board of Review calendar for a later township window.
Which Cook County townships have not announced their 2026 appeal dates?
Assessor filing dates remain unpublished for Rich, Bloom, North Chicago, Niles, Hanover, and South Chicago as of October 10. These records stay Pending until the official Cook County calendar confirms their dates. Do not treat an unannounced date as an open filing window.
Dates pending
Rich Township
The Cook County Assessor calendar has not published a 2026 opening or last-file date for this township as of October 10. No deadline has been inferred. Check the official calendar before filing.
Dates pending
Bloom Township
The Cook County Assessor calendar has not published a 2026 opening or last-file date for this township as of October 10. No deadline has been inferred. Check the official calendar before filing.
Dates pending
North Chicago Township
The Cook County Assessor calendar has not published a 2026 opening or last-file date for this township as of October 10. No deadline has been inferred. Check the official calendar before filing.
Dates pending
Niles Township
The Cook County Assessor calendar has not published a 2026 opening or last-file date for this township as of October 10. No deadline has been inferred. Check the official calendar before filing.
Dates pending
Hanover Township
The Cook County Assessor calendar has not published a 2026 opening or last-file date for this township as of October 10. No deadline has been inferred. Check the official calendar before filing.
Dates pending
South Chicago Township
The Cook County Assessor calendar has not published a 2026 opening or last-file date for this township as of October 10. No deadline has been inferred. Check the official calendar before filing.
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.