Is there a state income tax amount in box 11? If box 11 is blank or zero, you don't need the state ID. Just leave boxes 10a, 10b, and 11 blank in TurboTax. If there is a state income tax amount in box 11, enter IL for the state in box 10a. The state identification number is probably the same as the federal Payer's TIN. If you want to be sure, you would have to contact the state agency that issued the 1099-G and ask them what should be in box 10b.
