Send your Illinois tax return to the Department of Revenue in Springfield

The Illinois Department of Revenue processes all state income tax returns. Mail your completed return to the address listed in the instruction booklet that came with your tax forms — the address changes depending on whether you are filing a paper return and what type of return you are submitting. The main mailing address for individual income tax returns is 101 West Jefferson Street, Springfield, IL 62794.

If you are filing electronically instead of by mail, you do not send anything to a physical address. You file through approved tax software or a tax professional who submits your return directly to the Department of Revenue's computer system. Electronic filing is faster and reduces the chance of errors that delay processing.

The important date to file your Illinois return is the same as the federal important date — typically April 15, unless that date falls on a weekend or holiday. If you file by mail, your return must be postmarked by midnight on the important date date. Returns postmarked after the important date are considered late, even if they arrive at the Department of Revenue office on time.

Key Takeaways

  • Paper returns go to 101 West Jefferson Street, Springfield, IL 62794, but check your instruction booklet because the address may vary by return type.
  • Your return must be postmarked by the April 15 important date if you are mailing it; the postmark date is what counts, not the arrival date.
  • Electronic filing through tax software or a tax professional is faster and does not require a mailing address.
  • If you cannot file by the important date, you can request an extension from the federal government, which also extends your Illinois filing important date.

Paper return addresses by return type

The Illinois Department of Revenue lists different mailing addresses depending on which form you are filing. If you are filing Form IL-1040 (the standard individual income tax return), use the Springfield address above. Some residents file other forms — for example, Form IL-1040-X if you are amending a previous return, or Form IL-1040-NR if you are a nonresident.

Before you seal your envelope, open the instruction booklet that came with your tax forms or read the current version from the Illinois Department of Revenue website. The booklet lists the correct mailing address for your specific form. Using the wrong address delays processing because the mail has to be rerouted.

What to include with your return

Include all pages of your completed return, all required schedules, and all supporting documents the form asks for. Do not staple pages together — use a paper clip or rubber band instead, because the Department of Revenue scans returns and staples can jam the machines. Write your Social Security number clearly on the first page of your return.

If you are including a check for taxes owed, make it payable to "Illinois Department of Revenue" and write your Social Security number on the check. Do not send cash. Include the check in the same envelope as your return.

How long processing takes

The Illinois Department of Revenue typically processes paper returns within four to six weeks of receipt, though during the peak filing season (March and April) processing can take longer. If you are due a refund, you can track the status of your return on the Department of Revenue website by entering your Social Security number and the amount of your refund.

Electronic returns are processed much faster — usually within two to three weeks. If you are expecting a refund and want it sooner, filing electronically is the quickest option.

Filing an extension if you need more time

If you cannot file your return by April 15, you can request an automatic extension from the federal government on Form 4868. Filing a federal extension automatically extends your Illinois important date as well. You must request the extension by the April 15 important date, even if you are not ready to file your full return yet.

An extension gives you until October 15 to file your return, but it does not extend the important date to pay taxes owed. If you think you will owe money, estimate what you owe and send a payment with your extension request to avoid penalties and interest.

What to do if you cannot locate the correct address

The Illinois Department of Revenue website (tax.illinois.gov) publishes the current mailing addresses for all return types. You can also call the Department of Revenue at 217-782-3336 during business hours to confirm the address before you mail your return. Having the correct address takes five minutes and prevents your return from being delayed.

If you have already mailed your return to an incorrect address, contact the Department of Revenue as soon as possible. Provide them with the address you used and the date you mailed it. They can sometimes locate your return and reroute it, but the sooner you report the error, the better.

Frequently Asked Questions

Can I file my Illinois return electronically through the same software I use for federal taxes?

Yes. Most major tax software packages allow you to file both your federal and Illinois returns in the same session. The software will route your Illinois return to the Department of Revenue automatically. Check the software's list of states before you purchase to confirm Illinois is included.

What if I mail my return but it gets lost in the mail?

Mail your return using a method that provides tracking, such as certified mail or Priority Mail with tracking. Keep the receipt. If your return does not arrive, you have proof of when and where you mailed it. The Department of Revenue will not penalize you for a return lost in the mail if you can show you mailed it by the important date.

Do I need to mail my W-2 forms with my tax return?

No. Do not mail your W-2 forms to the Department of Revenue. Keep them with your records for at least three years. The Department of Revenue receives copies directly from your employer, so they already have the information on file.

Can I file my Illinois return if I live outside Illinois?

Yes, but you may file as a nonresident or part-year resident depending on how long you lived in Illinois during the tax year. Use Form IL-1040-NR for nonresident returns. The mailing address may differ from the standard address, so check the instruction booklet for Form IL-1040-NR before you mail your return.