March 25, 2026
Most people don't realize that the Cook County Assessor's Office isn't the only place to appeal your property tax assessment. If the Assessor denies your appeal — or if you missed the Assessor's window — there's a second level: the Cook County Board of Review.
The Cook County Board of Review (BOR) is an independent government body that hears property assessment appeals separately from the Assessor's Office. It's made up of three elected commissioners, and it accepts appeals from property owners who believe their assessment is incorrect or inequitable.
The BOR operates on its own calendar, which is separate from the Assessor's schedule. Even if you already appealed to the Assessor and lost, you can file again with the Board of Review.
Cook County has a two-step appeal system:
Level 1 — Cook County Assessor's Office This is where most appeals start. You file during the open window for your township (typically after assessment notices are mailed). The Assessor reviews your evidence and issues a decision.
Level 2 — Cook County Board of Review If the Assessor denies your appeal or doesn't reduce your assessment enough, you can file with the Board of Review. This is a separate hearing process with its own rules and forms.
Both levels operate on township-by-township schedules, so deadlines vary.
The BOR publishes its own township-by-township filing calendar at cookcountyboardofreview.com. Generally:
Check the BOR website for current open townships.
The Board of Review accepts several types of evidence:
Comparable sales (most effective) — Recent arm's-length sales of similar properties that suggest your home's market value is lower than your assessment implies. The BOR has a specific comparable grid format.
Unequal assessment — Evidence that similar properties in your area are assessed at lower rates. This is particularly useful when you can't find recent sales but can find neighbors with lower assessments on similar homes.
Property characteristic errors — If the Assessor has incorrect data on your property (wrong square footage, wrong number of bedrooms, non-existent improvements), document the error with photos and supporting records.
Income approach (investment properties) — For income-producing properties, evidence of actual rental income and expenses can support a lower valuation.
Gather your evidence. Comparable sales, photos, any Assessor-level decision letter.
Get your PIN. You'll need your 14-digit Property Index Number, found on your tax bill.
Complete the BOR appeal form. Download from cookcountyboardofreview.com or file online through their portal.
Submit before your township's deadline. Late filings are not accepted under any circumstances.
Attend the hearing (if scheduled). Many BOR appeals are decided on the written record. If a hearing is scheduled, you'll receive notice by mail.
The BOR typically processes appeals within a few months of your township's window closing. Decisions are mailed to the property address. If the BOR reduces your assessment, the reduction applies to your next tax bill.
If you disagree with the BOR's decision, you can appeal further to the Illinois Property Tax Appeal Board (PTAB) or the circuit court — but that level requires an attorney in most cases.
Homeowners who file with solid comparable sales evidence frequently win reductions. The savings depend on how far over-assessed your property is and the current tax rate in your area, but reductions of $500–$2,000 per year are common for residential properties.
Run a free assessment check at OverTaxed IL — we'll show you your current assessed value, find comparable sales, and tell you whether you have grounds for an appeal at either the Assessor or Board of Review level. If you do, we generate the complete appeal packet for you.
The window won't wait. Five minutes now could mean real money back in your pocket.