The homeowner's reading room
Missed your Cook County property tax appeal deadline?
First identify which office, township, and tax year the deadline belongs to. The Assessor and Board of Review have separate schedules, so one closed window does not tell you the status of the other.
1. Identify exactly which deadline passed
Write down your PIN, township, tax year, and the office named on the notice. Then check the Assessor's assessment and appeal calendar and the Board of Review's current announcements. Look for any official updates rather than relying on an old search result or social post.
Our township guides help you find local context. Confirm the actual filing window with the receiving office before submitting. A payment deadline on a tax bill and an assessment appeal deadline serve different purposes.
2. If the Assessor window closed, check the Board
The Board of Review's FAQ explains that it is independent of the Assessor and opens townships for appeals on its own schedule. Check whether your township is not yet open, currently open, or closed for the relevant year.
The Board offers preregistration through its online portal before a township opens. Read the portal's instructions carefully and keep its confirmation. Do not assume that starting a draft or assembling research is the same as completing a filing.
Use the waiting period to organize your property facts and evidence. Our office comparison and DIY appeal guide can help you prepare.
3. If both windows closed, separate the issues
For an ordinary Board assessment appeal, its FAQ says a closed township must wait for the next assessment year. A late appeal should not be assumed available. Check current official announcements in case the office has changed a window.
- You already received a Board decision: read the decision and its further-review instructions promptly. Our after-the-Board guide introduces that separate process.
- An exemption is missing from an issued bill: review the Assessor's Certificate of Error instructions for eligibility, available years, and documents.
- You believe an issued assessment contains an error: the Assessor has a separate valuation Certificate of Error process. Ask the office whether it fits your facts; do not treat it as an automatic extension of the ordinary appeal window.
Keep the distinction clear in your notes: a missed filing, a decision you want reviewed, and a correction request are not the same situation.
4. Build a small file for the next opening
Create a folder with the notice, property record, prior decisions, relevant photographs, and the source for each proposed correction. Add a one-page summary of the issue so you can pick up the work later.
For sales research, record the sale date, price, property characteristics, and why the property is comparable. Recheck the receiving office's evidence requirements when the next window opens; do not assume an old set of sales will remain equally useful.
The Assessor's FAQ says owners may appeal between reassessments when their township is open. You do not need to wait for another three-year reassessment notice to start watching the calendar.
A useful reminder names the township and office, links to the official calendar, and tells you what to check. “Check the Board's opening date for my township” is more actionable than “property taxes.”