The Old Montgomery County Courthouse, built in 1847, is a historic Greek Revival building located on the northwest corner of Third and Main streets in Dayton, Ohio. The limestone building, modeled on the 5th century BC Temple of Hephaestus in Athens, Greece, is the nation’s best surviving example of a Greek Revival style courthouse. The interior floor plan is modeled after the traditional Greek temple form and includes a high ceiling vestibule, center hall procession that leads to the rotunda and elliptical courtroom.
The design was suggested by Dayton citizen Horace Pease, who had a book of sketches of the Acropolis in Athens which showed the Temple of Theseus, which he admired. Pease showed it to the Montgomery County Commissioners, who also were favorably impressed, and agreed it would be a good model for their new Courthouse. They hired architect Howard Daniels of New York to draw the plans in which he captured the form and beauty of the ancient Greek temple.
The Courthouse was added to the National Register of Historic Places on January 26, 1970.