I was employed full-time in NY. However, I did contract work in IL and traveled there for two weeks. One week in NY. Do I need to file an Illinois return?

[KarenJ · Accepted solution]

You probably need to file an IL return. From the IL-1040 instructions, as an IL nonresident, you must file Form IL-1040 and Schedule NR if you earned enough IL taxable income from Illinois sources to have a tax liability (i.e., your Illinois base    income from Schedule NR, Step 5, Line 46, is greater than your Illinois exemption allowance on    Schedule NR, Step 5, Line 50), or you want a refund of any Illinois Income Tax withheld in error. You must attach a letter of explanation    from your employer.

Your exemption allowance would be less than the resident exemption allowance which is either $2,226 or $4,450 (depending on your filing status).  So if your IL income is greater than this, you will need to file.

You should prepare your IL nonresident return first before your NY state resident return so that TurboTax can calculate the credit you will receive on your NY return for the IL tax.

Please see below the instructions for the IL-1040 and the IL-Schedule NR

https://www2.illinois.gov/rev/forms/incometax/Documents/currentyear/individual/il-1040-instr.pdf

https://www2.illinois.gov/rev/forms/incometax/Documents/currentyear/individual/il-1040-schedule-nr-i...