The Rugby (PI5) and New Rockford post offices employ the same standardized plan. The exterior walls are of a light tan smooth brick and are modestly ornamented with limestone for window sills, panels below the windows, and a band of molding below the eaves. Above the entrance a federal eagle motif is set within a circular background of aluminum tracery backed by a glass-block transom. Edward “Buk” Ulreich painted the 12 x 7-foot lobby mural, Advance Guard of the West (1941), that is a stylized, fanciful depiction of a group of Native Americans in headdress on rearing horses and holding spears.