State tax filing
You should file a Wisconsin tax return like usual, reporting all of your wages, and reporting only the Wisconsin tax withheld. You may end up owing taxes to Wisconsin, since some taxes were paid to Illinois (which will be refunded separately)
Since you are filing the Illinois non-resident return solely to get a refund of Illinois tax, you will file the return and allocate $0 income to that state, assuming there was no other income earned in Illinois, just the wages you mentioned. Here's how to do this in TurboTax Online:
- When you start the Illinois return, answer that you made money in Illinois but never lived there.
- Tell TurboTax you lived in Wisconsin.
- Continue until you arrive to the screen "Tell us about your Illinois income." If as a hypothetical example, you earned a total of $129,000, but $50,000 was on your Illinois Box 16 line of the W-2, $50,000 will appear in the box "How much of the $129,000 dis you make while living in Wisconsin" automatically. Make this entry zero.
- Continue through the interview and make sure nothing has an Illinois share.
- Your return should calculate a refund of all the tax withheld in Illinois.
Here is some more information: Which states have reciprocal agreements?
