I'm a resident of Illinois and won a ~$4600 jackpot last year at a casino in Indiana. I'm filing my state tax returns this year. Indiana withheld $160 for state taxes. My Indiana return gave me a $4 refund. Now I'm filing my Illinois taxes on Illinois Free Webfile and it's saying my taxable income is my wages + the $4,600 I won. Is this correct? They're taxing me for something that Indiana already taxed me for. Illinois had nothing to do with me winning that $4600. Not sure if it's important but I declared $4,600 in losses on my federal return as well.

Actually, Illinois is taxing you on all your income but you will get a tax credit for the State Taxes paid in Indiana.

Many States including New Jersey tax you on your all income no matter where they come from, but, at the same time, you are entitled to a Tax Credit that was paid to the other State.

No State taxes you twice on any income generated from an other State, without giving you a Tax Credit, (an offset against Taxes paid to the other State).

Thus, your program is correct to tax you on the Gambling Winnings in Indiana, but, if you check the appropriate box, you would also be receiving a tax credit for the $160 taxes paid to Indiana State.

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