Illinois Board of Review Appeals: How They Work

What does a board of review decide?

The Illinois Department of Revenue lists four kinds of appeal a board of review hears: the market value is too high, the assessment level is above the local median, the property data is wrong, or similar neighboring homes are assessed lower. A board can lower the assessment, keep it, or raise it, and in Cook the Board hears only the current tax year.

That last point is worth knowing before you file. Outside Cook, boards may raise, lower or adjust any assessment before they finish their review, after notice to the owner. The Cook County Board can raise an assessment only after notifying you in writing and giving you a chance to be heard. DuPage starts that process with a notice to show cause, and McHenry's rules say its Board can confirm, reduce or increase any assessment.

When is the Board of Review deadline?

• DuPage, Lake, McHenry and Kendall: 30 days after your township's assessments are published. In DuPage, Lake and McHenry the townships publish on different dates, and DuPage rejects any appeal filed outside the 30-day period.
• Cook County: the Board opens townships in groups after the Assessor finishes them, and each group stays open at least 30 days. By law you get at least 20 days after the Board publishes a township's filing notice. Owners can pre-file before their township opens.

Talking to your township assessor first is encouraged in DuPage, Lake and Kendall, and Lake requires it for factual-error appeals. In DuPage that conversation does not extend the filing period. McHenry adds a separate catch: starting in 2026 it mails assessment notices only for properties the assessor changed, farms and new construction, so everyone else has to check the published list.

Each county page lists the township dates we track, with sources: Cook, DuPage, Lake, McHenry and Kendall. Townships have their own pages too, such as Hyde Park, York, Libertyville and McHenry Township. The full list is on the appeal deadlines page.

How do you file with each county's board?

DuPage, Lake, McHenry and Kendall each ask for their own comparison grid with the complaint. DuPage, Kendall and Lake want the evidence at filing too; Lake accepts later written evidence up to 5 business days before a hearing. In Cook, evidence can follow until the Board's evidence deadline for your group, and every filer includes a brief, a short written explanation. Our guide to Cook County Assessor vs. Board of Review appeals covers the Cook rules in more depth.

What happens at a Board of Review hearing?

Hearings are optional in most of these counties, and you can ask a board to decide on your written evidence. Cook holds owner hearings by phone and lets you waive the hearing without penalty. DuPage lets you choose a phone hearing or no appearance, and says every appeal is treated equally either way. Lake offers in-person or phone hearings, or a decision on the evidence, but does not reschedule them. Kendall hears appeals in person only.

DuPage mails written decisions after every hearing in the county is finished, typically the following March. In Cook you can ask for a Re-Review within 3 days of the decision letter, without new arguments.

What comes after the board of review?

A board of review decision can go to PTAB within 30 days of the decision notice (in Cook, or 30 days after the Board closes your township, if later), or to circuit court instead. In McHenry, a complaint the Board dismisses cannot go on to PTAB, so follow its filing rules closely. If PTAB lowers the assessment on an owner-occupied home, the reduction carries forward for the rest of the general assessment period unless the home sells.

Before any of this, it helps to know whether your assessment is out of line. Our free check compares your home with similar homes nearby using county records, and the Illinois property tax guide has the statewide rules.