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Illinois law

Tax Laws in Illinois.

Illinois tax disputes can involve individual and corporate income tax, sales and use tax, property tax, and employer withholding. Illinois state-tax analysis runs through the Illinois Department of Revenue, with administrative review through the Illinois Independent Tax Tribunal for income, franchise, and certain sales-tax matters, and judicial review in the Circuit Courts.

Last verified: 2026-04-17

State law

Statute of Limitations

Varies by tax type and notice; administrative deadlines are often short35 ILCS

Illinois tax disputes do not run on a single universal deadline. The timing depends on the type of tax, the notice or order issued, and the procedural path chosen in response.

State law

Filing Requirements

Preserve Every Revenue Notice

Illinois tax disputes are deadline-sensitive. Audit letters, assessment notices, refund denials, and collection correspondence should be preserved and reviewed immediately.

State law

Key Illinois Statutes

Illinois Revenue Code35 ILCS

35 ILCS covers Illinois state taxation, including income tax, sales and use tax, property tax, and procedural rules for assessments, refunds, and enforcement.

Illinois Independent Tax Tribunal35 ILCS 1010/

The Illinois Independent Tax Tribunal hears disputes over income, franchise, and certain sales-tax matters before judicial review.

State law

Official Sources

Not Legal Advice

This page summarizes publicly available statutes and rules for informational purposes only. It does not constitute legal advice, and no attorney-client relationship is created by viewing this content. Laws change — always verify with the primary source or consult a licensed attorney in Illinois.

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