This Greek Revival courthouse is the most beautiful representative of its era in western Pennsylvania. The commissioners asked Samuel and John Bryan, contractors from Harrisburg, to build a courthouse similar to their earlier work in Fayette County (now demolished). The red brick building features a portico with six two-story fluted Corinthian columns supporting a dentil-lined pediment. A tall domed and colonnaded cupola is topped with a statue of General Nathanael Greene doffing his hat; it was carved in 1998 by Miles Davin Sr. The courthouse's side elevations are articulated by brick pilasters springing from stone bases and display wide entablatures and simple dentiled cornices. Double wooden entrance doors are surmounted by a multipaned transom topped by a smaller version of the dentil-lined pediment. The courthouse has one large airy courtroom on the second floor that can be accessed by a curved set of double stairs located at the front of the building. The central hallway of the first story is lined with offices.
Directly behind the courthouse to the south stands a large two-and-one-half story, c. 1870 mansard-roofed sheriff's house, with a slightly projecting central bay, stone lintel, and sill bands. The red brick jail (c. 1880) southeast of the courthouse was recently demolished and replaced with a large three-story red brick office building.