AppealDesk

Cook County Property Tax Appeal, Illinois

Travis BunnTravis Bunn·Updated July 22, 2026

Watch: How to appeal your property taxes in Cook County

Cook County is the most populous county in Illinois and the second-most-populous county in the United States, with an estimated population of 5.2 million residents as of 2026. The county seat is Chicago, which is home to over 2.7 million residents, with other notable cities including Elgin, Cicero, Schaumburg, Evanston, and Arlington Heights. Cook County has some of the highest property taxes in the nation, with median annual property tax bills significantly exceeding both state and national averages. The county's effective property tax rate of approximately 1.89% to 1.98% is nearly double the national average, and the median annual property tax bill of $6,053 to $6,349 is more than double the national median of $2,690, making property tax appeals particularly valuable for Cook County homeowners.

Notable cities: Chicago, Elgin, Cicero, Schaumburg, Evanston, Arlington Heights

Median Home

$305,200

Tax Rate

1.98%

Annual Tax

$6,053

Population

5,200,459

On the typical Cook County home, valued near $305,200 at the county’s effective tax rate of 1.98%, an over-assessment of even 10% means you are overpaying year after year until you appeal it. Here is how to find out if yours qualifies.

2026 Appeal Deadline: 30 days from the date your reassessment notice is mailed

Cook County has a unique two-tier appeal system with rolling deadlines by township. Homeowners can appeal first to the Cook County Assessor's Office within 30 days of receiving their reassessment notice. The Assessor stage is optional. Property owners can then file a second appeal with the Cook County Board of Review during their township's designated Board of Review filing period, which is announced separately. Deadlines vary by township and are published throughout the year. Appeals must be filed before the township's specific closing date, and late filings are not accepted under any circumstances.

Want the full walkthrough? Read our Cook County Property Tax Appeal Guide with evidence strategies and hearing tips.

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Aerial view of an Illinois residential neighborhood. Cook County appeal guide.

How Cook County Assesses Property

33.33%of market value

Assessed by: Cook County Assessor's Office

Assessment cycle: triennial

Notices typically mailed: Late April through February (varies by township)

Cook County follows a triennial reassessment cycle, meaning properties are reassessed once every three years based on their township location. In Illinois, residential properties are assessed at 33.33% of their fair market value (though Cook County initially assesses at 10% before applying an equalization factor). For example, if your home's market value is $305,200, at Illinois's 33.33% assessment ratio your assessed value would be $101,733, resulting in approximately $6,053 in annual taxes at the county's effective rate of 1.98%.

The Appeal Process

Appeals are heard by the Board of Review. After filing your appeal, the Cook County Assessor or Board of Review will review your evidence and may schedule an informal hearing where you can present your case. The Board of Review conducts quasi-judicial hearings with commissioners who evaluate comparable sales, appraisals, and other evidence. Decisions are issued in writing, and successful appeals result in lower assessed values that will be reflected in your next property tax bill.

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Step 1: Determine your township and confirm your appeal deadline by checking your reassessment notice or visiting the Cook County Assessor's website calendar. Your deadline is typically 30 days from when your notice is mailed, and this date is printed on the notice.

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Step 2: Gather supporting evidence including 3-5 comparable sales of similar homes in your area that sold for less than your assessed value, a recent professional appraisal (if available), photographs documenting property condition issues, repair estimates for any major defects, and your property's purchase documents if recently acquired.

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Step 3: File your appeal online through the Cook County Assessor's Office online portal at cookcountyassessoril.gov during your township's filing period. Create an account, complete the appeal form with accurate property information, and upload all supporting documentation. Residential appeals (single-family homes, townhomes, properties with 6 or fewer units) can be filed online at no cost.

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Step 4: If your Assessor-level appeal is denied or you're unsatisfied with the result, file a second appeal with the Cook County Board of Review during your township's Board of Review filing period. You can skip the Assessor and file directly with the Board of Review if preferred. The Board provides an independent quasi-judicial hearing process where commissioners evaluate your evidence.

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Step 5: Attend a hearing if requested (optional but can strengthen your case). Present your comparable sales data, appraisal, photos, and other evidence to the Board of Review commissioners. The Board will review your case and issue a written decision, which typically takes 6-12 months to complete through both appeal tiers.

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Step 6: If denied by the Board of Review, you may file a final appeal with the Illinois Property Tax Appeal Board (PTAB) within 30 days of the Board of Review's decision, or alternatively file a tax objection complaint in the Circuit Court of Cook County. PTAB and Circuit Court are alternative remedies, not sequential steps.

Required form: Online appeal form through Cook County Assessor's Office portal (for Assessor-level appeals) or Cook County Board of Review portal (for Board of Review appeals)

Filing Methods

online:Cook County Assessor's Office online appeal portal at https://www.cookcountyassessoril.gov/online-appeals for residential properties (Class 2)
online:Cook County Board of Review online portal at https://www.cookcountyboardofreview.com - free to use for all property owners and attorneys
mail:Cook County Assessor's Office, 118 N. Clark Street, Room 320, Chicago, IL 60602
in-person:Visit Cook County Assessor's Office at 118 N. Clark Street, Room 320, Chicago, IL 60602 (appointment encouraged, call 312-443-7550)

Evidence to Bring

Comparable sales data (3-5 similar homes that sold for less)Recent professional appraisalPhotographs of property showing condition issuesRepair estimates for major defects or damagePurchase documents if recently acquiredProperty characteristic corrections if assessor's records are inaccurate

Cook County Assessor Contact

Cook County Assessor's Office

Phone: (312) 443-7550

Address: 118 N. Clark Street, Room 320, Chicago, IL 60602

Website: https://www.cookcountyassessoril.gov

Online Portal: https://www.cookcountyassessoril.gov/online-appeals

Hours: 8:30 a.m. - 5:00 p.m. Monday-Friday

Tax Exemptions in Cook County

General Homestead Exemption (Homeowner Exemption)

$10,000 reduction in EAV (saves $250 to $2,000 per year depending on local tax rates)

Available to homeowners whose property is their primary residence, this exemption reduces the equalized assessed value (EAV) of the home, lowering the property tax bill.

Eligibility: Must own and occupy the property as primary residence as of January 1 of the tax year. Must be responsible for paying property taxes.Deadline: Must apply by January 1 of tax year; applications after May 15, 2026 processed as Certificate of Error

Senior Citizen Homestead Exemption

$8,000 reduction in EAV (combined with Homeowner Exemption for total $18,000 reduction; saves up to $300-$750 per year)

Provides additional property tax relief for senior homeowners on top of the general homestead exemption.

Eligibility: Must be 65 years of age or older during the tax year, own and occupy the property as primary residence as of January 1.Deadline: Annual application required; Cook County Assessor's Office now automatically renews for properties not sold

Senior Citizen Assessment Freeze Exemption

Freezes assessed value at base year level

Freezes the assessed value of a senior's property to prevent increases, providing significant tax savings for qualifying low-income seniors.

Eligibility: Must be 65 or older, have household income under $65,000, and be enrolled in specific public assistance programs.Deadline: Annual application required using Form PTAX-340

Persons with Disabilities Exemption

$2,000 reduction in EAV annually

Provides property tax relief for disabled homeowners who occupy the property as their primary residence.

Eligibility: Must have a qualifying disability, occupy property as primary residence, and be responsible for paying property taxes. Must provide proof of disability.Deadline: Initial application with Form PTAX-343; automatically renewed if property ownership unchanged

Returning Veterans' Homestead Exemption

$5,000 reduction in EAV for two years after returning from active duty

Provides temporary property tax relief for veterans returning from active duty in armed conflict.

Eligibility: Must be a veteran returning from active duty in an armed conflict involving U.S. armed forces.Deadline: Apply with Cook County Assessor's Office

Veterans with Disabilities Exemption

Varies by disability percentage; up to $100,000 reduction for specially-adapted housing

Significant property tax relief for disabled veterans, with exemption amount based on disability percentage.

Eligibility: Must be a veteran with service-connected disability. Amount varies based on disability rating.Deadline: Apply with Cook County Assessor's Office with proof of disability rating

Cook County Appeal Packet · $49

Comparable sales evidence, county-specific filing guide, and professional cover letter. Enter your address to get started.

✓ All 50 states✓ Instant results✓ $49 flat fee

Frequently Asked Questions

What is the deadline to appeal my property taxes in Cook County?
The deadline to appeal your Cook County property taxes is typically 30 days from the date your reassessment notice is mailed by the Assessor's Office. The exact deadline is printed on your reassessment notice. Cook County has a unique township-by-township system with rolling deadlines throughout the year, so your specific deadline depends on which township your property is located in and when notices are mailed for that township. In 2026, south and west suburban townships are undergoing reassessment. Late filings are not accepted under any circumstances, and missing your deadline by even one day means you lose your appeal rights for that year.
How do I file a property tax appeal in Cook County online?
To file a property tax appeal online in Cook County, visit the Cook County Assessor's Office online portal at cookcountyassessoril.gov/online-appeals for residential properties. Create a free account, log in, and complete the online appeal form with your Property Index Number (PIN), property information, and evidence summary. You can upload supporting documentation including comparable sales, photographs, appraisals, and repair estimates directly through the portal. The online system is free to use and allows you to track your appeal status. If appealing to the Board of Review (the second level), use the Board of Review online portal at cookcountyboardofreview.com with similar steps. Both portals are user-friendly and most residential appeals can be completed in about 20 minutes.
What is the homestead exemption worth in Cook County?
The General Homestead Exemption (also called Homeowner Exemption) in Cook County reduces your home's equalized assessed value (EAV) by $10,000, which typically saves homeowners between $250 to $2,000 per year depending on local tax rates and assessment increases. Senior citizens age 65 and older qualify for an additional Senior Citizen Homestead Exemption worth an $8,000 reduction in EAV, which can be combined with the general exemption for a total $18,000 reduction, saving up to $300 to $750 annually when combined. These exemptions are applied automatically if you previously qualified, but first-time applicants must apply through the Cook County Assessor's Office. The exemption savings appear as deductions on your second installment property tax bill mailed during the summer.
Can I appeal my Cook County property taxes if my township wasn't reassessed in 2026?
Yes, you can still appeal your Cook County property taxes even if your township was not reassessed in 2026. Under Illinois Property Tax Code, every property owner has the right to appeal regardless of reassessment year. While 2026 is the reassessment year for south and west suburban townships, properties in the City of Chicago (reassessed in 2024) and north suburbs (reassessed in 2025) can still file appeals through the Cook County Board of Review during their township's designated Board of Review filing period. You may appeal if you recently purchased your property, if there's been a significant change in market conditions, if you have vacancy issues, or if you believe your assessment is simply too high compared to similar properties. The Board of Review provides annual appeal opportunities for all townships.
What evidence do I need for a successful Cook County property tax appeal?
The strongest Cook County property tax appeals include three to five comparable sales of similar homes in your neighborhood that sold for less than your assessed value, demonstrating that your property is overvalued. You should also provide a recent professional appraisal if available, as this carries significant weight with the Board of Review. Additionally, include clear photographs documenting any property condition issues such as foundation problems, roof damage, outdated systems, or deferred maintenance that affect your home's value. Repair estimates from licensed contractors for major defects strengthen your case. If you recently purchased the property, include your purchase documents showing the actual sale price. Finally, if the Assessor's records contain errors about your property's characteristics (square footage, number of rooms, lot size), provide documentation to correct these inaccuracies.
How long does it take to get a decision on my Cook County property tax appeal?
Cook County property tax appeals typically take 6 to 12 months to complete through both appeal tiers (Assessor level and Board of Review level). If you file only with the Cook County Assessor's Office, you may receive a decision within several months during the reassessment year. However, if you proceed to the Board of Review for a second appeal, the process takes longer as the Board must review hundreds of thousands of appeals each session. Changes resulting from successful appeals are reflected in your second installment tax bill the year following your reassessment. For example, successful appeals filed in 2026 will affect the property tax bill issued in summer 2027. If you appeal further to the Illinois Property Tax Appeal Board (PTAB) or Circuit Court, the process can take an additional 3 to 5 years to settle.
What happens at a Cook County Board of Review hearing?
At a Cook County Board of Review hearing, you will present your case to commissioners who have quasi-judicial authority to review and adjust property assessments. The hearing is your opportunity to present evidence including comparable sales data, appraisals, photographs of property condition issues, and any other documentation supporting your claim that your property is overvalued. You can request a hearing when filing your appeal, though it's optional. During the hearing, commissioners will review your evidence, may ask questions about your property, and evaluate whether your assessment should be reduced based on the facts presented. The Board is not bound by the Assessor's previous determination, so even if the Assessor denied your appeal, you can still receive a reduction at the Board level. After the hearing, you will receive a written decision, and if a reduction is granted, your lower assessment will be reflected in your next tax bill.
How much can I save by appealing my property taxes in Cook County?
The amount you can save by appealing your Cook County property taxes depends on how much your assessment is reduced and your local tax rate. With Cook County's effective tax rate of approximately 1.98%, every $10,000 reduction in your property's assessed value saves you roughly $198 per year in property taxes. For example, if you successfully reduce your home's market value assessment from $350,000 to $320,000, that $30,000 reduction translates to approximately $750 in annual tax savings at a 2.5% effective tax rate. Over the three-year reassessment cycle, that amounts to $2,250 in total savings. Given Cook County's high property values and tax rates, successful appeals commonly save homeowners $500 to $2,000 or more annually. Over 62,000 eligible Cook County homeowners collectively miss out on more than $43 million in potential savings by not claiming exemptions alone, and many more overpay by not appealing inflated assessments.

Official Resources

Cook County Assessor's Office Official Website →

Access property information, file appeals online, apply for exemptions, view assessment calendars, and find detailed information about the assessment process.

Cook County Board of Review Official Website →

File second-level appeals, check appeal status, view filing deadlines by township, and access the Board of Review online appeals portal.

Illinois Property Tax Appeal Board (PTAB) →

State-level appeal board for taxpayers who wish to appeal Board of Review decisions; provides forms, filing instructions, and hearing information.

Cook County Property Tax Portal →

Unified portal combining information from the Assessor, Board of Review, Clerk, Recorder of Deeds, and Treasurer for comprehensive property tax information and research.

For state-wide appeal information including Illinois's assessment ratio and deadlines, see our Illinois Property Tax Appeal Guide →

Considering professional help with your appeal? Compare pricing, coverage, and pros/cons in our Best Property Tax Appeal Services (2026) or browse side-by-side service comparisons →

More Illinois Counties

Adams County (Quincy)Champaign County (Champaign)DeKalb County (DeKalb)DuPage County (Naperville)Grundy County (Morris)Jefferson County (Mount Vernon)
← All Illinois property tax appeal info

Sources: https://www.cookcountyassessoril.gov | https://www.cookcountyboardofreview.com | https://smartasset.com/taxes/cook-county-illinois-property-tax-calculator | https://www.ownwell.com/blog/cook-county-property-tax-appeal-deadline | https://www.ptab.illinois.gov/getstarted.html | https://worldpopulationreview.com/us-counties/illinois/cook-county | https://www.cookcountyassessoril.gov/assessment-calendar-and-deadlines

Last verified: 2026-07-22