Oak Park Township property tax appeal, Cook County
The median residential assessment in Oak Park Township rose 22.9% at its 2026 reassessment, and of the appeals decided for tax year 2025, 14.0% of 2,596 at the Assessor changed the value and 38.4% of 4,083 at the Board of Review ended in a decrease. Appeals for tax year 2026 close 18 Jun 2026 at the Cook County Assessor — verified 25 Sep 2026.
When Oak Park Township can appeal
| Where you appeal | Opens | Closes | Date we verified it |
|---|---|---|---|
| Cook County Assessor | 06 May 2026 | 18 Jun 2026 | 25 Sep 2026 |
| Cook County Board of Review | 03 Aug 2026 | 01 Sep 2026 | 25 Sep 2026 |
From the Assessor’s and Board of Review’s published 2026 calendars. Dates can change; confirm with the office before filing.
Oak Park Township Board of Review and Assessor appeal results by year
| Tax year | Closed Assessor appeals | Share that changed the value | Board of Review appeals | Share decreased |
|---|---|---|---|---|
| 2023 | 9,486 | 37.2% | 8,148 | 47.1% |
| 2024 | 3,154 | 12.7% | 4,719 | 47.9% |
| 2025 | 2,596 | 14.0% | 4,083 | 38.4% |
Residential property classes (class 2, including condominium units). An Assessor appeal counts as changed when the Assessor’s record says the value changed; a Board of Review appeal counts as decreased when its result is “Decrease”. Shares aren’t printed from fewer than 30 appeals. Past outcomes don’t predict the result of any one appeal.
Oak Park Township assessment increase, year on year
| Assessment year | Homes assessed in both years | Median change |
|---|---|---|
| 2024 | 17,044 | +0.0% |
| 2025 | 17,047 | +0.0% |
| 2026 | 17,014 | +22.9% |
Assessor mailed values for class 2 properties in Oak Park Township, compared with the same property’s value the year before. Cook County reassesses one of its three regions (South for this township) each year; in other years the median change is usually 0%. The latest year can be partial while notices are still being mailed. 17,063 residential parcels are in the township today.
Oak Park Township appeals: common questions
When is the Oak Park Township appeal deadline?
For tax year 2026, the Cook County Assessor window for Oak Park Township opened 06 May 2026 and closes 18 Jun 2026. We last verified that date against the office’s published calendar on 25 Sep 2026; dates move, so confirm with the office before you file.
What are the odds an appeal in Oak Park Township works?
In tax year 2025, 14.0% of the 2,596 closed residential appeals the Assessor decided for Oak Park Township changed the assessed value, and 38.4% of the 4,083 residential appeals the Board of Review decided ended in a decrease. Those are township-wide rates from closed cases, not a prediction for any one property.
Should I appeal to the Assessor or the Board of Review in Oak Park Township?
They are separate filings and the table above shows both. For 2025, Oak Park Township sent 2,596 residential appeals to the Assessor and 4,083 to the Board of Review; 14.0% and 38.4% of them respectively moved the value. The Board of Review hears appeals after the Assessor has closed a township, so missing the first window does not end the year.
How much did assessments go up in Oak Park Township?
At the 2026 reassessment the median residential assessment rose 22.9%, measured across the 17,014 class-2 properties the Assessor valued in both 2025 and 2026. That is the middle of the township, not your property: half the homes moved more.
What if the Oak Park Township window has already closed?
Nothing on this page files an appeal for you, and a closed window can’t be reopened here. The figures above are per tax year, so the same tables tell you what the next year’s filing looks like; the free assessment check compares your home with near-identical homes nearby whenever you run it.
Every answer here restates a figure printed elsewhere on this page. Nothing is added that we haven’t measured and sourced.
- Your own property: use the free assessment check, which compares your home with near-identical homes nearby.
- Tax bills, tax rates and exemptions.
- Commercial property and appeals filed with the Property Tax Appeal Board.
- Legal advice. CivicDelta doesn’t file appeals.
More: how a Cook County assessment appeal works · all 38 Cook County townships compared · everything we hold on property · how we compute these figures