I rent in KY (which is my mailing address), but my perm address is in OH and so is work. Where do I file, OH or KY?

[SweetieJean]

 Where is your driver's license, car registration, voting registration, etc?   According to the Kentucky Instructions, a Kentucky Resident is an individual that spends at least 183 days in Kentucky during the tax year.

[Hal_Al]

It depends on more details. Why do you have this arrangement? 

On the face of it  "I rent in KY" trumps "my perm address is in OH" in determining residency.  One common exception: if you renting in KY to attend school there, you would still be an OH resident.

As to filing; what state did you employer withhold for? KY & OH have a reciprocal agreement: they don't tax each other's residents for working in the other state.

[TomD8]

You may have a situation of dual residency.

OH regards you as a resident for tax purposes if your domicile (your main, primary home) is in Ohio.

KY regards you as a resident for tax purposes if you maintain a place of abode and spend more than 183 days of the tax year in KY.

In such a situation you would be both a domiciliary resident of OH and a statutory resident of KY.  Meaning you'd have to file as a resident in each of the two states.  In my experience, TurboTax does not handle dual residency situations very well.

Another factor is that KY law states that, in such a situation, reciprocity does not apply.  See Section (4) of this reference:

https://revenue.ky.gov/DOR%20Training%20Materials/103%20KAR%2017.140.%20Individual%20income%20tax%20...

Since reciprocity would not apply in this situation, if you had to file as a resident in both states you ought to be able to claim a credit on your KY return for the taxes paid to OH.  ("Other state credits" are typically not permitted when reciprocity exists.)

So your filing instructions come down to whether or not you spent more than 183 days in KY.