topic Do I need to include my Federal Tax Forms with my Illinois State Tax return? in State tax filing

Do I need to include my Federal Tax Forms with my Illinois State Tax return?

jlmaggi — Tue, 03 Feb 2026 07:49:33 GMT

Helping my son file his taxes for the first time. He is filing for the first time in Illinois and needs to snail mail in his IL-1040. TurboTax only had us print the IL-1040, but do we need to include his electronically filed Federal 1040 in the snail mail as well? I cannot find a direct answer online - or one that makes sense to me at least.

Re: Do I need to include my Federal Tax Forms with my Illinois State Tax return?

xmasbaby0 — Wed, 26 Feb 2025 19:28:54 GMT

Yes. When you mail a return to IL they want a copy of the federal too. When you choose to file by mail, the pages you need to mail will print out for you.

Re: Do I need to include my Federal Tax Forms with my Illinois State Tax return?

jlmaggi — Wed, 26 Feb 2025 19:34:42 GMT

Thank you. I appreciate it.

I was confused since TurboTax only had me print the IL-1040. It was odd as we got all the way to sending the returns via eFile and TurboTax popped up a notice stating we had to mail in the IL return, but filed his Federal and MO State Returns electronically.