Mostly just pass through Ohio on trips back east from Colorado so we are far from experts on the state. We stopped in the town of Clifton on the last trip and found it very photogenic. There is an old mill and many old buildings. Google it for info. Last year we spent a night in Marietta on our return trip and really liked the town. There are several covered bridges around the town.
Looking forward to other suggestions for us to photograph when passing through.