Property Tax Due Dates in Illinois

Illinois has one of the most distinctive property tax systems in the country: taxes are paid one year in arrears. This means the taxes you pay in 2025 are for the 2024 tax year. This delayed billing cycle can catch new homeowners off guard — when you purchase a home in Illinois, you will typically receive a credit at closing for the prior year's unpaid taxes. Property taxes in Illinois are administered at the county level. County assessors (or township assessors in some areas) set property values, the county board of review hears appeals, the county clerk calculates tax rates, and the county treasurer bills and collects. Tax rates vary significantly depending on the number of overlapping taxing districts — counties, municipalities, school districts, park districts, fire protection districts, and others — affecting your property.

Illinois property taxes are generally paid in two installments, though timing varies by county: Cook County: First installment: Due March 1 Second installment: Due August 1 Other counties: Many follow a June and September schedule, but dates vary. Contact your county treasurer for exact due dates. Late payments accrue interest at 1.5% per month (18% annually). If taxes remain unpaid for an extended period, the county may sell the tax lien to investors at an annual tax sale, which can ultimately lead to loss of the property if the lien is not redeemed. Most counties offer online payment through the county treasurer's website. Contact your county treasurer to confirm whether partial payments are accepted.

Illinois offers several exemptions that reduce your property's Equalized Assessed Value (EAV), directly lowering your tax bill: General Homestead Exemption — Owner-occupied primary residences receive an EAV reduction of $10,000 in Cook County and $6,000 in all other counties. File once; no annual renewal required after the initial application. Senior Citizen Homestead Exemption — Homeowners 65 or older receive an additional EAV reduction of $8,000 in Cook County and $5,000 in other counties. Senior Citizen Assessment Freeze — Income-qualifying seniors (household income under $65,000) can freeze their EAV at a base year level, preventing future assessment increases. Annual renewal is required. Persons with Disabilities Exemption — A $2,000 EAV reduction for qualifying disabled homeowners. Veterans with Disabilities Exemptions — Veterans with a 30–49% disability rating receive a $2,500 reduction; 50–69%: $5,000 reduction; 70% or higher: full exemption from all property taxes. Apply for exemptions with your county assessor's office. Many exemptions require annual renewal.

In Illinois, you can appeal your property assessment to the county board of review, with a second-level appeal available to the Illinois Property Tax Appeal Board (PTAB): Deadline: Appeals to the county board of review must be filed within 30 days of the publication of the assessment roll (also called the assessment notice). In Cook County, townships are reassessed on a rotating schedule throughout the year, so the publication date varies by township — watch for the publication date specific to your township. Steps: 1. Review your assessment notice and compare your assessed value to recent sales of similar properties. 2. File a complaint with your county Board of Review within the filing window. 3. Submit evidence: comparable sales, a recent independent appraisal, or documentation of property condition issues. 4. If still unsatisfied, appeal to the Illinois Property Tax Appeal Board (PTAB) within 30 days of the Board of Review decision. Cook County note: Properties in Cook County are reassessed every three years (with different townships reassessed in different years). The Board of Review accepts complaints separately for each township's reassessment.