How to appeal a Cook County, IL property assessment
✓ Verified — Last verified October 24, 2026
Filing details published for Cook County. Match the notice and assessment cycle to the official instructions.
Official appeal instructionsNot tax or legal advice; confirm with your county.
Filing timing
Notice-dependent instructions
Typically 30 days after the reassessment notice; use the last filing date printed on the notice and the township calendar.
Official source. Verified .
Where to file
Cook County Assessor’s Office; online appeals or paper forms.
Official source. Verified .
Assessment notice period
Reassessment mailing dates vary by township; consult the assessment calendar.
Official source. Verified .
Official offices
Fritz Kaegi
Sources for these instructions
https://rpie.cookcountyassessor.com/appeals
Typically, you have 30 days to file an appeal after receiving your reassessment notice. The last date to file an appeal for that year is printed on your notice.
Verified October 24, 2026
https://rpie.cookcountyassessor.com/appeals
We encourage the filing of appeals online. Please read our complete guide to online appeals before filing. If you are unable to file an appeal online, you can find paper forms here.
Verified October 24, 2026
Continue with your property
Common questions
Where do I file a Cook County assessment appeal?
Cook County Assessor’s Office; online appeals or paper forms.