Illinois property tax appeals, 2027
In Illinois, you appeal a property assessment to the County Board of Review, and the deadline is 30 days after the township assessment list is published (Cook County uses township filing windows). Each county below lists its own date, how to file and who hears the appeal. Sale prices are public record here, so recent sales of similar homes are the main evidence of market value.
Data as of 20 Oct 2026 · 102 counties, state and county recordsHow appeals work in Illinois
| Rule | What applies |
|---|---|
| What you argue | Market value as of January 1 of the assessment year (35 ILCS 200/9-95); uniformity is also recognized (35 ILCS 200/16-55(a); 35 ILCS 200/12-30(b)(9)) |
| How homes are assessed | Outside Cook, 33⅓% of fair cash value (35 ILCS 200/9-145), enforced by township equalization factors (9-210). Cook County classifies: Class 2 residential at 10% of market value. A state equalization factor (multiplier) is then applied to Cook assessments. Use the market value on the notice.. Outside Cook, 33⅓% of fair cash value (35 ILCS 200/9-145), enforced by township equalization factors (9-210). Cook County classifies: Class 2 residential at 10% of market value. A state equalization factor (multiplier) is then applied to Cook assessments. Use the market value on the notice. |
| Deadline | 30 days after the township assessment list is published (35 ILCS 200/16-55(d)). In Cook County, 30 business days after the assessor’s notice (12-55), then the Board of Review’s township filing window (at least 20 days after its notice, 16-110). |
| First appeal to | County Board of Review |
| What the notice shows | Market value as “Fair Market Value”; assessed value as “Assessed Value”. Mails: Only when the assessment changes; Cook County mails by township on a rolling schedule through the year, other counties after the assessment list is published (often summer to fall) |
| Sale prices public | Yes |
| Statutes | Grounds: 35 ILCS 200/16-55(a) (Cook: 16-95); fair cash value 1-50. Filing: 35 ILCS 200/16-55(d) (Cook: 16-110, 12-55). Assessor’s evidence: 35 ILCS 200/9-20 (property record cards are public); 16-55(i-5) (assessor’s evidence served 5 days before hearing where rules require advance evidence). |
More: how to read your notice · what a ratio is · evidence that works · deadlines in every state
Every Illinois county
| County | Deadline | Appeal rate | Lowered | Coverage |
|---|---|---|---|---|
| Cook County | Not yet published | — | — | Scan from recent sales |
| DuPage County | Not yet published | — | — | Scan from recent sales |
| Lake County | Not yet published | — | — | Scan from recent sales |
| Will County | Not yet published | — | — | Scan from recent sales |
| Kane County | Not yet published | — | — | Scan from recent sales |
| McHenry County | Not yet published | — | — | Scan from recent sales |
| Winnebago County | Not yet published | — | — | Scan from recent sales |
| Madison County | Not yet published | — | — | Scan from recent sales |
| St. Clair County | Not yet published | — | — | Scan from recent sales |
| Champaign County | Not yet published | — | — | Scan from recent sales |
| Sangamon County | Not yet published | — | — | Scan from recent sales |
| Peoria County | Not yet published | — | — | Scan from recent sales |
| McLean County | Not yet published | — | — | Scan from recent sales |
| Kendall County | Not yet published | — | — | Scan from recent sales |
| Rock Island County | Not yet published | — | — | Scan from recent sales |
| Tazewell County | Not yet published | — | — | Scan from recent sales |
| LaSalle County | Not yet published | — | — | Scan from recent sales |
| Kankakee County | Not yet published | — | — | Scan from recent sales |
| DeKalb County | Not yet published | — | — | Scan from recent sales |
| Macon County | Not yet published | — | — | Scan from recent sales |
| Vermilion County | Not yet published | — | — | Scan from recent sales |
| Williamson County | Not yet published | — | — | Scan from recent sales |
| Adams County | Not yet published | — | — | Scan from recent sales |
| Whiteside County | Not yet published | — | — | Scan from recent sales |
| Grundy County | Not yet published | — | — | Scan from recent sales |
| Boone County | Not yet published | — | — | Scan from recent sales |
| Jackson County | Not yet published | — | — | Scan from recent sales |
| Ogle County | Not yet published | — | — | Scan from recent sales |
| Knox County | Not yet published | — | — | Scan from recent sales |
| Henry County | Not yet published | — | — | Scan from recent sales |
| Coles County | Not yet published | — | — | Scan from recent sales |
| Macoupin County | Not yet published | — | — | Scan from recent sales |
| Stephenson County | Not yet published | — | — | Scan from recent sales |
| Woodford County | Not yet published | — | — | Scan from recent sales |
| Clinton County | Not yet published | — | — | Scan from recent sales |
| Franklin County | Not yet published | — | — | Scan from recent sales |
| Marion County | Not yet published | — | — | Scan from recent sales |
| Jefferson County | Not yet published | — | — | Scan from recent sales |
| Livingston County | Not yet published | — | — | Scan from recent sales |
| Monroe County | Not yet published | — | — | Scan from recent sales |
| Effingham County | Not yet published | — | — | Scan from recent sales |
| Lee County | Not yet published | — | — | Scan from recent sales |
| Christian County | Not yet published | — | — | Scan from recent sales |
| Morgan County | Not yet published | — | — | Scan from recent sales |
| Fulton County | Not yet published | — | — | Scan from recent sales |
| Bureau County | Not yet published | — | — | Scan from recent sales |
| Randolph County | Not yet published | — | — | Scan from recent sales |
| Montgomery County | Not yet published | — | — | Scan from recent sales |
| Logan County | Not yet published | — | — | Scan from recent sales |
| McDonough County | Not yet published | — | — | Scan from recent sales |
| Iroquois County | Not yet published | — | — | Scan from recent sales |
| Saline County | Not yet published | — | — | Scan from recent sales |
| Jo Daviess County | Not yet published | — | — | Scan from recent sales |
| Fayette County | Not yet published | — | — | Scan from recent sales |
| Jersey County | Not yet published | — | — | Scan from recent sales |
| Shelby County | Not yet published | — | — | Scan from recent sales |
| Perry County | Not yet published | — | — | Scan from recent sales |
| Douglas County | Not yet published | — | — | Scan from recent sales |
| Crawford County | Not yet published | — | — | Scan from recent sales |
| Hancock County | Not yet published | — | — | Scan from recent sales |
| Union County | Not yet published | — | — | Scan from recent sales |
| Piatt County | Not yet published | — | — | Scan from recent sales |
| Bond County | Not yet published | — | — | Scan from recent sales |
| Edgar County | Not yet published | — | — | Scan from recent sales |
| Warren County | Not yet published | — | — | Scan from recent sales |
| Wayne County | Not yet published | — | — | Scan from recent sales |
| Carroll County | Not yet published | — | — | Scan from recent sales |
| Richland County | Not yet published | — | — | Scan from recent sales |
| De Witt County | Not yet published | — | — | Scan from recent sales |
| Mercer County | Not yet published | — | — | Scan from recent sales |
| Clark County | Not yet published | — | — | Scan from recent sales |
| Lawrence County | Not yet published | — | — | Scan from recent sales |
| Moultrie County | Not yet published | — | — | Scan from recent sales |
| Pike County | Not yet published | — | — | Scan from recent sales |
| Massac County | Not yet published | — | — | Scan from recent sales |
| Washington County | Not yet published | — | — | Scan from recent sales |
| Ford County | Not yet published | — | — | Scan from recent sales |
| White County | Not yet published | — | — | Scan from recent sales |
| Johnson County | Not yet published | — | — | Scan from recent sales |
| Clay County | Not yet published | — | — | Scan from recent sales |
| Cass County | Not yet published | — | — | Scan from recent sales |
| Mason County | Not yet published | — | — | Scan from recent sales |
| Menard County | Not yet published | — | — | Scan from recent sales |
| Marshall County | Not yet published | — | — | Scan from recent sales |
| Greene County | Not yet published | — | — | Scan from recent sales |
| Wabash County | Not yet published | — | — | Scan from recent sales |
| Cumberland County | Not yet published | — | — | Scan from recent sales |
| Jasper County | Not yet published | — | — | Scan from recent sales |
| Hamilton County | Not yet published | — | — | Scan from recent sales |
| Schuyler County | Not yet published | — | — | Scan from recent sales |
| Brown County | Not yet published | — | — | Scan from recent sales |
| Henderson County | Not yet published | — | — | Scan from recent sales |
| Edwards County | Not yet published | — | — | Scan from recent sales |
| Putnam County | Not yet published | — | — | Scan from recent sales |
| Stark County | Not yet published | — | — | Scan from recent sales |
| Scott County | Not yet published | — | — | Scan from recent sales |
| Pulaski County | Not yet published | — | — | Scan from recent sales |
| Gallatin County | Not yet published | — | — | Scan from recent sales |
| Alexander County | Not yet published | — | — | Scan from recent sales |
| Calhoun County | Not yet published | — | — | Scan from recent sales |
| Pope County | Not yet published | — | — | Scan from recent sales |
| Hardin County | Not yet published | — | — | Scan from recent sales |
Illinois questions
When is the property tax appeal deadline in Illinois?
30 days after the township assessment list is published (35 ILCS 200/16-55(d)). In Cook County, 30 business days after the assessor’s notice (12-55), then the Board of Review’s township filing window (at least 20 days after its notice, 16-110). Counties publish the exact date, and most notices print it.
Who hears a property tax appeal in Illinois?
The County Board of Review hears the first appeal (35 ILCS 200/16-55(d) (Cook: 16-110, 12-55)).
How is a home assessed in Illinois?
At Outside Cook, 33⅓% of fair cash value (35 ILCS 200/9-145), enforced by township equalization factors (9-210). Cook County classifies: Class 2 residential at 10% of market value. A state equalization factor (multiplier) is then applied to Cook assessments. Use the market value on the notice., valued as of January 1 of the assessment year (35 ILCS 200/9-95).
What does a Illinois assessment notice show?
The market value, labeled “Fair Market Value”, and the assessed value, labeled “Assessed Value”. Notices mail: Only when the assessment changes; Cook County mails by township on a rolling schedule through the year, other counties after the assessment list is published (often summer to fall).
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- 35 ILCS 200/9-145 (33⅓% statutory level)
- 35 ILCS 200/16-55 (board of review complaints)
- 35 ILCS 200/12-30 (mailed notice, counties under 3,000,000)
- 35 ILCS 200/12-55 (Cook assessor notice and appeals)
- 35 ILCS 200/16-110 (Cook Board of Review filing)
- 35 ILCS 200/31-25 (transfer declaration)
- Cook County Assessor, Your Assessment Notice and Tax Bill (residential AV = 10% of FMV)
- Cook County Assessor, Guide to Property Assessment Appeals
- Each county’s own appeal instructions and notices, read on the date shown on each county page.
- U.S. Census Bureau, county population estimates (2024).