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Cook County publishes the result of every appeal it decides. So we counted 133,526 house appeals and 217,670 condominium appeals from 2024, split them by township, and worked out where an appeal's actually worth filing.
Now that spread is the part that really matters. A homeowner in the best township is roughly three times more likely to win than one in the worst, on exactly the same paperwork. Nobody publishes this, so people end up filing blind.
Just got your notice? Here's what each number on it means and how it turns into your bill.
Cook County doesn't have one deadline. The Assessor opens a few townships at a time through the year, and the Board of Review opens its own separate window for each township after that. Your township is printed on your assessment notice. Townships still taking appeals are listed first.
| Township | Assessor appeal | Board of Review appeal |
|---|---|---|
| Lake | Open until 10/29/2026 | Not scheduled yet |
| Palatine | Open until 11/4/2026 | Not scheduled yet |
| Lyons | Closed for this round | Open until 11/6/2026, evidence by 11/16/2026 |
| Northfield | Closed for this round | Open until 11/6/2026, evidence by 11/16/2026 |
| Orland | Open until 11/6/2026 | Not scheduled yet |
| Stickney | Closed for this round | Open until 11/6/2026, evidence by 11/16/2026 |
| West Chicago | Closed for this round | Open until 11/6/2026, evidence by 11/16/2026 |
| Jefferson | Open until 11/12/2026 | Not scheduled yet |
| Schaumburg | Open until 11/19/2026 | Not scheduled yet |
| Thornton | Open until 11/23/2026 | Not scheduled yet |
| North Chicago | Open until 11/24/2026 | Not scheduled yet |
| Niles | Open until 12/3/2026 | Not scheduled yet |
| Rich | Open until 12/4/2026 | Not scheduled yet |
| Hanover | Open until 12/7/2026 | Not scheduled yet |
| Bloom | Not on the calendar yet | Not scheduled yet |
| South Chicago | Not on the calendar yet | Not scheduled yet |
| Barrington | Closed for this round | Not scheduled yet |
| Berwyn | Closed for this round | Closed 9/29/2026 |
| Bremen | Closed for this round | Not scheduled yet |
| Calumet | Closed for this round | Not scheduled yet |
| Cicero | Closed for this round | Closed 9/29/2026 |
| Elk Grove | Closed for this round | Closed 9/29/2026 |
| Evanston | Closed for this round | Closed 9/1/2026 |
| Hyde Park | Closed for this round | Not scheduled yet |
| Lake View | Closed for this round | Closed 9/29/2026 |
| Lemont | Closed for this round | Not scheduled yet |
| Leyden | Closed for this round | Not scheduled yet |
| Maine | Closed for this round | Closed 9/29/2026 |
| New Trier | Closed for this round | Closed 9/1/2026 |
| Norwood Park | Closed for this round | Closed 9/1/2026 |
| Oak Park | Closed for this round | Closed 9/1/2026 |
| Palos | Closed for this round | Closed 9/29/2026 |
| Proviso | Closed for this round | Not scheduled yet |
| River Forest | Closed for this round | Closed 9/1/2026 |
| Riverside | Closed for this round | Closed 9/1/2026 |
| Rogers Park | Closed for this round | Closed 9/1/2026 |
| Wheeling | Closed for this round | Not scheduled yet |
| Worth | Closed for this round | Not scheduled yet |
| Township | House appeals | Won | Typical cut | Next reassessed |
|---|---|---|---|---|
| North Chicago | 1,541 | 30.2% | 7.8% | 2027 |
| Jefferson | 20,148 | 27.6% | 6.1% | 2027 |
| Hyde Park | 2,950 | 26.4% | 7.7% | 2027 |
| Lake | 9,172 | 25.3% | 7.1% | 2027 |
| South Chicago | 1,502 | 24.4% | 6.7% | 2027 |
| West Chicago | 4,054 | 24.1% | 7.2% | 2027 |
| Cicero | 1,285 | 23.6% | 7.5% | 2029 |
| Lake View | 5,869 | 23.1% | 5.9% | n/a |
| Lyons | 5,409 | 18.9% | 6.7% | 2029 |
| Thornton | 5,782 | 18.9% | 7.2% | 2029 |
| Northfield | 3,852 | 18.8% | 6.2% | 2028 |
| Hanover | 1,890 | 18.6% | 6.2% | 2028 |
| Wheeling | 4,772 | 18.1% | 5.7% | 2028 |
| Rich | 2,774 | 17.8% | 6.9% | 2029 |
| Rogers Park | 1,661 | 17.7% | 6.4% | 2027 |
| Proviso | 4,443 | 17.6% | 6.1% | 2029 |
| Bloom | 2,906 | 17.5% | 6.6% | 2029 |
| Worth | 6,258 | 17.3% | 5.7% | 2029 |
| Orland | 5,222 | 17.2% | 6% | 2029 |
| Evanston | 1,572 | 16.7% | 6.8% | 2028 |
| Riverside | 784 | 16.6% | 8% | 2029 |
| Norwood Park | 952 | 16.4% | 6.9% | 2028 |
| Leyden | 3,685 | 16.2% | 6.7% | 2028 |
| Schaumburg | 3,610 | 15.9% | 5.9% | 2028 |
| Niles | 4,277 | 15.4% | 6.1% | 2028 |
| Stickney | 1,331 | 15.2% | 5.2% | 2029 |
| Palos | 1,739 | 14.8% | 8.3% | 2029 |
| New Trier | 4,051 | 14.3% | 7.6% | 2028 |
| Barrington | 986 | 13.8% | 9.9% | 2028 |
| Oak Park | 2,544 | 13% | 6.2% | 2029 |
| Lemont | 1,597 | 13% | 7.4% | 2029 |
| Berwyn | 1,460 | 12.9% | 8% | 2029 |
| River Forest | 782 | 12.1% | 6.9% | 2029 |
| Maine | 4,023 | 11.1% | 8.2% | 2028 |
| Bremen | 2,280 | 10.2% | 5.9% | 2029 |
| Palatine | 3,983 | 9.2% | 6.2% | 2028 |
| Elk Grove | 2,258 | 9.2% | 6% | 2028 |
| Calumet | 122 | 8.2% | 11.1% | 2029 |
So the argument that decides Illinois residential appeals is uniformity, which basically just means showing that homes genuinely like yours are assessed lower than yours is. Now that's backwards from most states, where you'd argue market value from recent sales. In Washington, comparing your assessment to a neighbor's isn't even allowed as evidence.
And the board takes the best comparables from both sides, works out what each one's assessed per square foot of living area, and asks where you fall in that range. Above it, they grant. Inside or below it, they don't.
There's a fuller write-up of the method and the 351,196 cases behind it in what actually happens to Cook County property tax appeals.
Cook County gives you two separate free appeals at two different offices. The Assessor opens your township's window once a year, and the Board of Review opens its own afterwards in a different building. It takes the same evidence, and its evidence deadline falls ten days after its filing deadline, so you can file first and send the evidence after that. Missing the Assessor isn't missing the year.
And your township page carries today's dates for both.
So Cook County doesn't have one deadline. The Assessor opens a few townships at a time through the year, and the Board of Review opens its own separate window for each township after that. Your township's printed on your assessment notice, and the table above has the dates for both.
Basically, you've got two separate free appeals. First the Cook County Assessor, then the Board of Review, which takes the same evidence and lets you send it up to ten days after its filing deadline. So missing the Assessor isn't missing the year.
Illinois decides most home appeals on uniformity, which basically means showing that homes genuinely like yours are assessed lower per square foot of living area. If you sit above that range, the board grants. Inside it or below it, it doesn't.
In 2024, 19.4 percent of 133,526 Cook County house appeals won a reduction, and 18.9 percent of condominium appeals did. It runs from 9.2 to 30.2 percent depending on your township, and the table above has every one.
Honestly, only if your home's assessed higher per square foot than homes genuinely like it nearby. Our free check runs exactly that comparison from the county's own records and tells you which side you're on. Check my home free.
Every figure above comes from the Cook County Assessor's published appeals dataset for tax year 2024, counting cases where the certified value came in below the mailed value. Houses are classes 202 through 210, 234 and 278. Condominiums are class 299. The reassessment years were derived from the county's own published assessed values and matched against the Assessor's triennial grouping.