Illinois Property tax appeals and assessment disputes

Illinois has specific statutory protections that govern property tax appeals and assessment disputes. Knowing your rights is the first step; enforcing them requires a formal written demand letter that cites the relevant Illinois statutes, sets a firm deadline, and states the legal consequences of non-compliance. TaxFightLetter generates exactly that letter — tailored to Illinois law, your specific dispute, and your timeline. Below are the 10 dispute types we cover for Illinois residents.

Property tax in Illinois is governed by the Illinois Property Tax Code (35 ILCS 200/1-1 et seq. (appeals: 35 ILCS 200/16-160; PTAB: Article 16, Div. 5)). Assessment cycle: General (quadrennial) reassessment every four years in most counties; Cook County reassesses on a triennial (three-year) cycle by geographic triad. Assessment date is January 1 of the tax year. Assessed value: 33 1/3% (one-third) of fair market value statewide (the Illinois Department of Revenue targets a 33.3% level of assessment). Cook County uses classification: approximately 10% for residential and 25% for commercial/industrial, reconciled via a state equalization multiplier.

Illinois Dispute Types

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