This window has closed
The Board of Review appeal window for Oak Park Township opened August 3, 2026 and closed September 1, 2026. Appeals are filed township by township in Cook County, so nothing can now be filed at the Board of Review for Oak Park for tax year 2026.
The county stage for 2026 is over in Oak Park. Both the Assessor and the Board of Review windows have closed. If you filed and the decision left you assessed too high, the next step is the state: an appeal to the Illinois Property Tax Appeal Board, due within 30 days of the later of the Board's written decision or the date the Board sends its final action on your township to the Assessor. Otherwise the next Oak Park window is the 2027 cycle, and we can have the parcel reviewed before it opens.
What the Board of Review window means for Oak Park homeowners
Cook County property owners get two cracks at an assessment each year: first at the Assessor, then at the Board of Review. The two are independent — a loss (or a pass) at one does not prevent filing at the other, and the Board decides tens of thousands of residential appeals every cycle. Oak Park sits in Cook County's south triad; in a reassessment year the whole township's values move at once, which is when uniformity appeals matter most.
What Oak Park appeals actually did, year by year
These are county-published outcomes for ALL residential (Class 2) appeals filed in Oak Park Township — every appellant, represented or not, not this firm's results:
| Tax year | Venue | Appeals decided | Received a reduction | Avg. cut (of AV, winners) |
|---|---|---|---|---|
| 2026 | Assessor | 5,945 | 1,604 (27%) | 8.1% |
| 2025 | Board of Review | 3,608 | 1,553 (43%) | 7.0% |
| 2025 | Assessor | 2,349 | 362 (15%) | 7.6% |
| 2024 | Board of Review | 4,239 | 2,185 (52%) | 7.2% |
| 2024 | Assessor | 2,839 | 392 (14%) | 7.8% |
| 2023 | Board of Review | 5,300 | 3,092 (58%) | 7.9% |
| 2023 | Assessor | 5,792 | 2,119 (37%) | 10.4% |
| 2022 | Board of Review | 2,799 | 965 (34%) | 6.7% |
| 2022 | Assessor | 1,597 | 241 (15%) | 11.8% |
| 2021 | Board of Review | 3,879 | 1,671 (43%) | 7.2% |
| 2021 | Assessor | 2,712 | 351 (13%) | 10.3% |
Read these within their year: reassessment years pull win rates and cut sizes around for the whole township, so the fair comparison is same-year, same-class, same-venue.
Oak Park's tax math: what an appeal is worth here
The median Oak Park residential assessment is about $45,000 of assessed value. At the 2025 state equalizer (3.03) and Oak Park's average local rate (~11.67%), that assessment produces roughly $15,912 of gross tax before exemptions. Among last cycle's successful Oak Park appeals, the average reduction was about 7.0% of assessed value — on the median home, arithmetic of roughly $1,114 per year. Your parcel's numbers are what matter: run them in the calculator.
What you can still do in Oak Park
- Look up your parcel and see how its assessment per square foot compares with similar Oak Park homes. That comparison is the case, and it is worth knowing whether you have one before the next window opens.
- Watch the deadlines page, which tracks every township and venue as the county publishes dates.
- If the assessment is wrong on the county's own record — the wrong square footage, a building that is gone, an exemption you were entitled to and did not get — that is a Certificate of Error, and it is not bound by this window. See the appeal FAQs.
Fees are contingency-only (no upfront cost), and there is no fee at all if an assessment is not reduced.
What happens if you did file
The Board of Review reviews the complaint against its own records and the comparables submitted. Most residential appeals are decided on the papers — no hearing, no visit, and in practice a residential appeal results in either a reduction or no change. Decisions typically arrive after the township closes, and a certified change flows into the second-installment bill.
If you missed this window
The two venues are sequential: an Oak Park owner who misses the Board of Review window is done for this cycle at the county level, though a Board decision can be taken to the Illinois Property Tax Appeal Board within 30 days of the later of the Board's written decision or the date the Board sends its final action on your township to the Assessor, and the following year brings both windows again. The deadlines page tracks every township's next window as the county publishes it.
