State taxes due, but to what state?

When she started working there she should have notified them of her address, and should have noticed that paychecks were withholding taxes in IL.

You must file an IL return and say are a non-resident and no IL source income, and request a refund of all IL tax withheld.

Also need to file a return for the third state where she worked and declare all the income earned while she worked there. It's my understanding that companies are required to withhold taxes based on where you work, and multiple states if necessary, but most don't do that. Also I don't think employees file in the states they work.

When she started working there she should have notified them of her address, and should have noticed that paychecks were withholding taxes in IL.

You must file an IL return and say are a non-resident and no IL source income, and request a refund of all IL tax withheld.

Also need to file a return for the third state where she worked and declare all the income earned while she worked there. It's my understanding that companies are required to withhold taxes based on where you work, and multiple states if necessary, but most don't do that. Also I don't think employees typically don't file in the various states they work, but they should. In your home state tax return you get a credit for tax paid to the other state (or vice versa), but as your home state has no tax this is not an issue.

really ? she "worked" for the consulting company based in IL, was paid by the consulting company, and not at the client..... regardless of the location of the "work performed" ?

Really. The employee had no connection to Illinois except that that's where the employer is located. So is Boeing. That doesn't mean that every Boeing employee, no matter where, pays Illinois income tax.

Phil Marti VITA/TCE Volunteer Clarksburg, MD