The Logan County Courthouse is a historic Second Empire building located on the southeastern corner of Main Street and Columbus Avenue in downtown Bellefontaine, Ohio, United States. Built in 1870 at a cost of $105,398.08, the courthouse was constructed primarily of locally mined sandstone, and it is covered with a mansard roof. The courthouse is adjacent to Court Avenue, the first concrete street in the United States. On June 4, 1973, it was added to the National Register of Historic Places.