Living in a
particular state only for the purpose of attending school probably will not
establish residency in that state. You may still have to file a tax return in
that state if you have taxable income there, but you would file as a
non-resident.
Residency is based
on the concept of domicile. Your domicile is the place where you have family
connections, lived and/or worked, belong to a house of worship, and, most
importantly, the place to which you intend to return after you have been
away. Once you have domicile somewhere, it remains until you move away and abandon the intent to return.
So, if your domicile
was the state that you moved from to attend school, and you intend to return
there, barring future events (such as a post-graduation job offer), then that
state is still your domicile, and is the place where you are a resident for tax
purposes.
You will still need to file a nonresident income tax return, accounting for the income earned from you contractor job, in Ohio. And you will include that income in your tax return for your home state, but should receive a tax credit to reduce the effects of double taxation.
Finally, be careful about the drivers license. Changing your license does not change your domicile. You should be aware that some states require you to have an in-state license if you are both living and holding a job in that state.
