1099 forms in Illinois

jrosenblatt6 — Mon, 23 Feb 2026 13:55:39 GMT

What 1099 forms need to be attached to Illinois State tax returns?

Re: 1099 forms in Illinois

DawnC — Tue, 28 Mar 2023 22:26:48 GMT

If you are mailing your Illinois tax return, you should include copies of any 1099 with Illinois state withholding reported on it.

Attach a completed Schedule IL-WIT and all withholding forms (W-2s, 1099s, etc.) to support the amount you claim as Illinois Income Tax withheld on Line 25. Form IL-1040 instructions. See Tips to Speed Up Processing on page 2

TurboTax will generate and print a Filing Instructions page which will list what you need to include along with the mailing address.