Well, since the two border each other, it would have to be the actual state line.
Somerset, Pennsylvania is about halfway between Cleveland Ohio and Columbia Maryland
If you take follow I-70, Dayton, Ohio, would be the halfway point.
Pineton, Pennsylvania is halfway between Ohio and Asbury
Sugar Grove, Ohio is the halfway point.
The halfway point between Colerain, Ohio and Crete, Illinois is in RIchmond, Indiana.
Silver Springs, OH is the halfway point.
The halfway point between Lorain, Ohio and New Castle, Pennsylvania falls in or around Mantua, Ohio.
Halfway between Columbus and Cincinnati
Honeybee, KY is the halfway point.
Cambridge, Ohio is pretty close to halfway.
The halfway point between Dallas, Texas and Warren, Ohio is in Centerville, Tennessee.
Halfway between Standish Michigan and Findlay ohio