COOK COUNTY PROPERTY TAX APPEALS
FREE PROPERTY TAX APPEAL REVIEW
Tell us about the property. We’ll review it and contact you about your options.
CONFIDENTIAL INTAKE
Confidential inquiry. No reduction, no attorney fee.
2026 DEADLINE TRACKER · VERIFIED OCTOBER 12, 2026
2026 Cook County property tax appeal deadlines
As of October 12, 2026, Cook County Assessor appeals are open in Leyden through October 14; Worth through October 15; Wheeling through October 22; Proviso through October 27; Lake Township through October 29; Palatine through November 4; Orland through November 6; Jefferson through November 12; Schaumburg through November 19; Thornton through November 23; and North Chicago through November 24. The Board of Review is open for Lyons, Northfield, Stickney, and West Chicago through November 6, with evidence due November 16 for timely complaints.
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 October 12, 2026, Cook County Assessor appeals are open in Leyden through October 14; Worth through October 15; Wheeling through October 22; Proviso through October 27; Lake Township through October 29; Palatine through November 4; Orland through November 6; Jefferson through November 12; Schaumburg through November 19; Thornton through November 23; and North Chicago through November 24. The Board of Review is open for Lyons, Northfield, Stickney, and West Chicago through November 6, with evidence due November 16 for timely complaints.
How do I know which deadline applies to my property?
In Cook County, the controlling window is tied to the property’s township and the office accepting appeals. Confirm the township from the PIN, identify whether the Assessor or Board of Review is open, and use the official source linked below.
What happens if my township’s deadline recently closed?
You generally cannot use an Assessor filing window after it closes. A later Cook County Board of Review window or another remedy may be available, but eligibility and timing depend on the agency 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?
Fifteen verified Cook County filing windows are open as of October 12: eleven at the Assessor and four at the Board of Review. Leyden closes first on October 14, followed by Worth on October 15. The latest Assessor deadline is North Chicago on November 24.
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
The 2026 Cook County Board of Review Group 3 complaint window is open October 8 through November 6. The separate evidence-submission deadline for timely complaints is November 16.
COOK COUNTY
OPEN
Northfield Township — Board of Review
The 2026 Cook County Board of Review Group 3 complaint window is open October 8 through November 6. The separate evidence-submission deadline for timely complaints is November 16.
COOK COUNTY
OPEN
Stickney Township — Board of Review
The 2026 Cook County Board of Review Group 3 complaint window is open October 8 through November 6. The separate evidence-submission deadline for timely complaints is November 16.
COOK COUNTY
OPEN
West Chicago Township — Board of Review
The 2026 Cook County Board of Review Group 3 complaint window is open October 8 through November 6. The separate evidence-submission deadline for timely complaints is November 16.
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 calendar, updated October 11, lists an October 8 notice/open date and November 23 last file date. This is not a Board of Review deadline.
COOK COUNTY
OPEN
North Chicago Township
The Cook County Assessor calendar, updated October 11, lists an October 9 notice/open date and November 24 last file date. This is not a Board of Review deadline.
Which property tax appeal deadlines are opening soon?
No verified Cook County window is currently in Opening soon. Thornton, North Chicago, and the Board of Review Group 3 townships are already open. Unpublished dates remain in Dates pending until an official source confirms them.
Which Cook County filing windows recently closed?
Hyde Park closed at the Assessor on October 8. The Board of Review Group 2 complaint window closed September 29, and its separate evidence deadline passed October 9. A closed Assessor window does not determine a separate Board of Review window, which must be checked on the Board’s official calendar.
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. Confirm any later Board of Review window on the Board's official calendar.
Recently closed
Palos Township — Board of Review
The 2026 Cook County Board of Review Group 2 complaint window closed September 29. The separate evidence-submission deadline for timely complaints was October 9.
Recently closed
Maine Township — Board of Review
The 2026 Cook County Board of Review Group 2 complaint window closed September 29. The separate evidence-submission deadline for timely complaints was October 9.
Recently closed
Lakeview Township — Board of Review
The 2026 Cook County Board of Review Group 2 complaint window closed September 29. The separate evidence-submission deadline for timely complaints was October 9.
Recently closed
Elk Grove Township — Board of Review
The 2026 Cook County Board of Review Group 2 complaint window closed September 29. The separate evidence-submission deadline for timely complaints was October 9.
Recently closed
Cicero Township — Board of Review
The 2026 Cook County Board of Review Group 2 complaint window closed September 29. The separate evidence-submission deadline for timely complaints was October 9.
Recently closed
Berwyn Township — Board of Review
The 2026 Cook County Board of Review Group 2 complaint window closed September 29. The separate evidence-submission deadline for timely complaints was October 9.
Recently closed
Lemont Township
The 2026 Cook County Assessor filing window closed September 29. Confirm any later Board of Review window on the Board's official calendar.
Recently closed
Bremen Township
The 2026 Cook County Assessor filing window closed September 24. Confirm any later Board of Review window on the Board's official calendar.
Recently closed
Barrington Township
The 2026 Cook County Assessor filing window closed September 23. Confirm any later Board of Review window on the Board's official calendar.
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 still have dates pending?
Rich, Bloom, Niles, Hanover, and South Chicago township dates are pending. The Cook County Assessor has not published their 2026 notice/open dates or filing deadlines, so no date is inferred.
Dates pending
Rich Township
The Cook County Assessor has not published a 2026 notice/open date or last file date. No date is inferred; check the official calendar for an announcement.
Dates pending
Bloom Township
The Cook County Assessor has not published a 2026 notice/open date or last file date. No date is inferred; check the official calendar for an announcement.
Dates pending
Niles Township
The Cook County Assessor has not published a 2026 notice/open date or last file date. No date is inferred; check the official calendar for an announcement.
Dates pending
Hanover Township
The Cook County Assessor has not published a 2026 notice/open date or last file date. No date is inferred; check the official calendar for an announcement.
Dates pending
South Chicago Township
The Cook County Assessor has not published a 2026 notice/open date or last file date. No date is inferred; check the official calendar for an announcement.
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.