Seneca County Ohio (Historic Districts) has 6 places on the National Register of Historic Places including 2 places of Statewide significance. Significant places include Downtown Tiffin Historic District and National Orphans' Home, Junior Order United American Mechanics, Fort Ball-Railroad Historic Disrict, Fostoria Downtown Historic District and North Sandusky Street Historic District.
The famous person Luther Hall is associated with one of more of the Seneca County historic places. Prominent architectural styles found in Seneca Country are Italianate, Bungalow/Craftsman and Greek Revival.