The Miami County Courthouse is an historic building in Troy, Ohio, United States. Built in 1885, it was designed by noted Ohio (and later New York) architect, Joseph W. Yost, who also designed the similar Belmont County Courthouse built at the same time in St. Clairsville. It has high arched windows, Corinthian columns supporting the outthrust corners and main entrance. A flight of stairs runs to the main entrance. The central pediment rests on an arch supported by Corinthian columns.