2025 Cook County Property Tax Appeal Deadlines – Open Townships & How to File

Introduction

Every year the Cook County Assessor’s Office reassesses property values. These assessments directly affect your property tax bill. If you believe your assessment is too high, you have the right to appeal.

The appeal process has two levels:

1. File with the Cook County Assessor’s Office.

2. If necessary, file with the Cook County Board of Review.

Each township has its own opening and closing dates for appeals, and missing the window can cost you money. Below is the current appeal status for 2025.

Current 2025 appeal status – Cook County Board of Review

The Board of Review handles second-level appeals. As of late August, the Board has opened appeals for Group 2B townships only. These townships opened on August 18, 2025 and will close on September 16, 2025. Homeowners in these townships should file before the closing date.

The open townships and their deadlines are:

- Elk Grove– open August 18, closes September 16, 2025.

- Lake View – open August 18, closes September 16, 2025.

- Lyons – open August 18, closes September 16, 2025.

- New Trier – open August 18, closes September 16, 2025.

Townships in pre-file phase

The Board of Review allows taxpayers to pre-file appeals before the official opening date. Pre-filing doesn’t start the appeal clock but ensures you’ll be notified when your township’s filing window opens.

Townships currently in the pre-file phase include: Barrington, Bloom, Bremen, Calumet, Hanover, Hyde Park, Jefferson, Lake, Lemont, Leyden, Maine, Niles, North Chicago, Northfield, Orland, Palatine, Proviso, Rich, Schaumburg, South Chicago, Stickney, Thornton, West Chicago, Wheeling, and Worth.

Homeowners in these townships should gather evidence (comparable property values, photos, and documents) and be ready to file when notified.

Current 2025 appeal status – Cook County Assessor’s Office

The Cook County Assessor’s Office is the first stop for tax appeals. Appeals remain open for several townships and close soon. Property owners must file within this window; if you miss it, you must wait until next year.

Below are the townships that remain open for first-level appeals and their deadlines:

- Lemont – open for appeals until September 2, 2025.

- Leyden– open for appeals until September 2, 2025.

- Calumet – open for appeals until September 11, 2025.

- Hyde Park – open for appeals until September 16, 2025.

- Worth– open for appeals until September 23, 2025.

- Wheeling – open for appeals until September 30, 2025.

- Jefferson – open for appeals until October 3, 2025.

- Proviso – open for appeals until October 7, 2025.

Closed townships

Several townships – including Berwyn, Cicero, Evanston, Norwood Park, Oak Park, Palos, River Forest, Riverside, and Rogers Park – already had their Board of Review filing windows this year and are currently closed.

If your property is in one of these townships and you missed the deadline, you cannot file a 2025 Board of Review appeal and must wait until next year. However, you may still qualify for exemptions or other relief; consult the Assessor’s Office for guidance.

Why file a property tax appeal?

- Assessments are not always accurate. Computer-generated valuations can overstate the market value of your home. An appeal allows you to correct errors and ensure you are taxed fairly.

- Lower taxes. A successful appeal can reduce your assessment, which directly lowers your property tax bill. In some cases, reductions last multiple years, saving thousands of dollars.

- Protect your investment. Keeping your tax bill in line with comparable properties preserves your home’s value and can make your property more attractive to buyers.

How to file an appeal

1. Gather evidence. Compile comparable property sales, photos showing discrepancies (e.g., functional obsolescence or deferred maintenance), and other documents that support a lower value.

2. File with the Assessor’s Office. For townships currently open, submit your appeal online through the Assessor’s portal before the last filing date. You typically have 30 days from the mailing date of the reassessment notice to file, so act quickly.

3. Review the decision.The Assessor will issue a decision after reviewing your evidence. If you disagree with the outcome, you may appeal further.

4. Appeal to the Board of Review. Once your township’s Board of Review window opens, you may file a second-level appeal. Pre-filing is available for many other townships.

Tips for success

- Mark your calendar. Appeal windows are short. Use the dates above to plan and set reminders.

- Don’t wait to file. You can submit your appeal as soon as your township opens; waiting until the deadline leaves little time to correct errors or gather additional evidence.

- Check both agencies. The Assessor’s Office and the Board of Review have separate filing periods. Even if you appealed with the Assessor, you may still need to appeal with the Board of Review to get relief.

- Consult a professional attorney. Property tax appeals can be complex, and working with an experienced attorney can dramatically increase your chances of success. An attorney can navigate deadlines, prepare evidence, and advocate on your behalf.

Conclusion

Filing a property tax appeal is one of the most effective ways to reduce your tax burden and protect your investment. The process can be confusing and time-sensitive, which is why partnering with an experienced attorney is highly recommended.

At CookCountyTaxAppeal.com, we provide tools such as our property tax calculator so you can easily compare your property taxes. Visit us today to explore your options and start your path toward a fair property tax bill.

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Hani Khatib: Attorney at Law, CPA, and LL.M. in Taxation