Cook County, Illinois · checked 9 October 2026
Cook County property tax appeal deadlines 2026
The Assessor opens appeals one township at a time, for about 30 days after notices are mailed. Ten townships are still open this autumn. Filing is free and online, and you don't need a lawyer.
Still open with the Assessor
| Township | Last day to file | Main towns |
|---|---|---|
| Leyden | Wed 14 Oct | Franklin Park, Northlake, Melrose Park (part), River Grove |
| Worth | Thu 15 Oct | Oak Lawn, Evergreen Park, Alsip, Chicago Ridge, Worth |
| Wheeling | Thu 22 Oct | Arlington Heights, Wheeling, Prospect Heights, Mount Prospect (part) |
| Proviso | Tue 27 Oct | Maywood, Bellwood, Westchester, Hillside, Broadview, La Grange Park |
| Lake (Chicago) | Thu 29 Oct | Back of the Yards, Englewood, Chicago Lawn, Garfield Ridge |
| Palatine | Wed 4 Nov | Palatine, Rolling Meadows, Inverness |
| Orland | Fri 6 Nov | Orland Park, Orland Hills, Tinley Park (part) |
| Jefferson (Chicago) | Thu 12 Nov | Portage Park, Jefferson Park, Belmont Cragin, Edison Park |
| Schaumburg | Thu 19 Nov | Schaumburg, Hoffman Estates (part), Roselle (part) |
| Thornton | Mon 23 Nov | Calumet City, Dolton, South Holland, Lansing, Harvey |
Not yet open: Bloom, Rich, Hanover, Niles, North Chicago and South Chicago. Their dates will appear on the Assessor's calendar. Town lists are a guide; your notice names your township.
Already closed this year
Hyde Park closed on 8 October. Calumet, Lemont, Bremen, Barrington, Northfield, Lyons, West Chicago, Stickney and the spring townships (including Evanston, New Trier, Oak Park, Maine, Lakeview, Elk Grove, Palos and Cicero) closed earlier. If yours is one of them, you can usually still appeal to the Board of Review when it opens your township, and if that fails, to the state Property Tax Appeal Board. Check the Board of Review's dates.
How to file with the Assessor
- Find your 14-digit PIN on your reassessment notice or tax bill.
- Check whether your home is over-assessed. Cook County homes are assessed at 10% of market value, so an assessed value of $35,000 means the Assessor thinks your home is worth $350,000. If similar homes nearby sold for less, or are assessed lower, you have a case.
- Gather 3 to 5 comparable sales from the last year or two: same area, similar size, age and style. Photos of any damage or needed repairs help too.
- File online at the Assessor's appeals page before 11:59 pm on your township's last day. There's no fee.
- Keep your confirmation. Results usually come out a few months later, and you can still go to the Board of Review afterwards.
Is it worth it?
Often, yes. In a reassessment year, notices can jump sharply, and the Assessor regularly reduces values when owners show real comparable sales. Every $1,000 cut in assessed value saves roughly the local tax rate times $1,000 times the state multiplier each year until the next reassessment, usually 3 years. Our free check estimates your saving in about a minute.
Check if my home is over-assessed
Source: Cook County Assessor, Assessment & Appeal Calendar, read 9 October 2026. Dates can change; the date on your own notice is the one that counts.