2026 Cook County property tax reassessment guide
Cook County is reassessing the south and west suburban townships in 2026. Homeowners receive new proposed values township by township, followed by short Assessor appeal windows and later Board of Review opportunities.
Check your 2026 assessment against similar Cook County homes.
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Open 2026 reassessment-township guides
These Simple Tax Appeal township guides are currently within their published Assessor filing windows. Cook County publishes additional township dates as the cycle progresses, so verify the official calendar before filing.
What changes in a reassessment year?
Cook County follows a triennial reassessment cycle. In the scheduled reassessment area, the Assessor mails a new notice showing the property's updated estimated fair market value and assessed value. That notice is the trigger to verify the record and decide whether the new assessment should be appealed.
The data can lag the letter
The Assessor's current calendar notes that updated values can take an additional business day to appear online after the reassessment notice date. If you just received a notice and public data still looks stale, recheck the official property record before relying on an appeal comparison.
What should a homeowner check first?
- Deadline: confirm the Assessor's last-file date for the township.
- Property facts: check square footage, class, age, basement, garage, baths, and other recorded characteristics.
- Uniformity: compare the assessment with genuinely similar homes in the same area.
- Market value: consider whether recent purchase or market evidence contradicts the County's estimate.
- Sequence: use the Assessor first while that opportunity is open, then the Board of Review if needed.
A bigger assessment increase is not automatically a stronger appeal
The useful question is whether the resulting assessment is supportable. Two neighboring homes can both rise sharply and still be treated uniformly. A stronger uniformity argument shows that physically credible comparable homes ended up assessed more favorably than the subject.
Cook County uniformity appeal guide →Official 2026 source
Cook County's current assessment calendar identifies the south and west suburbs as the scheduled 2026 reassessment area and publishes each township's notice and appeal dates as they become available.
Use the current 2026 data to see whether the evidence supports an appeal.
Status uses the Chicago/Central calendar date. Cook County updates township dates throughout the year; always verify the official calendar before filing.