Since you ended up back in Ohio, Ohio will be considered your permanent tax residence for 2017 and you will be considered a Non-Resident of Mississippi. Part-year Resident forms won't work in this particular scenario.
Your permanent
tax residence is the state which will expect you to file a Resident tax
return. This means that all your income will be reported to Ohio,
and you will file a Non-Resident tax
return for Mississippi, reporting your income earned only
for that state.
The U.S. Supreme Court ruled against double taxation in 2015,
stating that two or more states are no longer permitted to tax the same
earnings. So, if you live in Ohio but work in Mississippi and pay taxes on
that income in Mississippi, Ohio cannot tax you on it as well. Ohio must offer you a credit for taxes you paid elsewhere. Be certain to complete your Non-Resident Mississippi return first, as you will need the tax paid information to calculate your Ohio credit.
