Do I have to pay income tax on gambling winnings if I already paid the tax in the state where I won the money?
If you were an Illinois resident when the gambling winnings were earned, you must pay Illinois Income Tax on the gambling winnings. However, you may include the gambling winnings in the non-Illinois portion of Schedule CR, Credit for Tax Paid to Other States. Only non-Illinois gambling winnings can be included in the non-Illinois portion of your Schedule CR,Column B.
Note: For tax years ending on or after December 31, 2019, you must pay Illinois Income Tax on Illinois gambling winnings, including sports wagering winnings, regardless of your residency.