Important Notices
2026 Tax Filing Season Begins January 26 for Individuals
The Illinois Department of Revenue is accepting 2025 Individual Income Tax Returns on Monday, January 26, the same day the IRS opens the federal filing season for individuals. The deadline to file Illinois individual returns is Wednesday, April 15, 2026.
The Illinois Department of Revenue is currently accepting 2025 Business Income Tax Returns.
Available Tax Forms:
Have you received a letter or Final Notice of Tax Due assessing an Estimated Payment Penalty?
Learn why you received this letter from IDOR by visiting our webpage Letters and Notices for Individual Income Tax (illinois.gov).
Response Options for Identity Verification Letters
If you received an identity verification letter from the Illinois Department of Revenue, you can respond electronically by selecting the option that matches your letter: enter a code, take a quiz, or attach documents. No MyTax Illinois account is required. For more information, see Identity Verification Letters Information.
Featured Programs
Trending Resources
Frequent Questions
Trending Forms
- CRT-61 - Certificate of Resale (Registered Retailers/Resellers)
- 2025 IL-1040, Individual Income Tax Return, Instructions, and Schedules
- Illinois Business Registration
- 2026 Withholding (Payroll) Tax
- RUT-50 Instructions
- RUT-25 Instructions
- Power of Attorney
- ST-1, Sales and Use Tax Return
- STAX-1, Application for Sales Tax Exemption