The Armstrong County Courthouse, dramatically sited against a steep hillside at the eastern terminus of Kittanning's Market Street, is one of eight remaining Greek Revival courthouses in western Pennsylvania. Constructed by Hulings and Dickey for Barr and Moser, the courthouse includes features usually found late in the style's popularity. The pediment and four columns, the tall windows on the second floor, the roundels above, and the ornate cupola that crowns the building are all typical of the Greek Revival. However, the Roman Corinthian columns and the ground-floor windows topped with semicircular arches are characteristic of a newer fashion. The cruciform plan building has a wide stairway at the east, or rear, elevation. The interior was extensively and unsympathetically remodeled by Kittanning and Ford City architect Tillman Scheeren Jr. in the mid-twentieth century. The courtroom ceiling, originally twenty-three feet high and covered with frescoes, was unfortunately lost in this remodeling. The courthouse is Kittanning's third courthouse, and the second on this site. It has a fairly discrete wing of 1991 at the south; to the north is the jail.