Courthouses today, often, house only the courts with room for no one else. Most courthouses are at the center of town. Most likely, the downtown formed around the courthouse not the other way around. The exceptions are in Wood and Ottawa counties. Their courthouses are a few blocks off the main streets of what their cities' downtowns are today.
Most courthouses are old.
However, one of the newest true courthouses is also the most boring and that's in Champaign County . The courthouse in downtown Urbana is in 1960's style architecture and is inclined to remind you more of a post office or police station than the kind of place you expect of a courthouse. The most unique one is also the oldest one in Ohio. It's in Meigs County where many of the county elected officials have an outside entrance to their office. The courthouse looks more like an old, southern estate mansion than a building you'd find in an Ohio county seat.