Oak Park Cemetery, sixty-eight acres of gently sloping, tree-shrouded land southeast of Oak Park Road, is bounded by an adjoining cemetery, Graceland, on the northeast and by the deep ravine of Neshannock Creek on the south. It was laid out by real estate developer P. J. Watson, who built homes in Neshannock Heights and had the foresight to realize that people in new homes would ultimately need new burial grounds. Oak Park Cemetery soon eclipsed the popularity of New Castle's older, larger cemetery, Greenwood. The first burials date from 1894, and the small Gothic Revival chapel appears contemporaneous. There are two outstanding burial vaults: William Patterson's Egyptian Revival–style crypt c. 1905 with stained glass depicting the Holy Family's flight to Egypt, and John Knox's c. 1909 crypt that is shaped like a small Greek temple. The largest structure on the property is a granite mausoleum with space for four hundred burials built by the American Mausoleum Company between 1912 and 1914. The rectangular, flat-roofed building, sheathed in random stone, is dominated by a balustraded entrance pavilion supported by Tuscan columns. The porch shelters a double metal door with simple, smooth ashlar trim around a metal lunette. The building's overall effect is foreboding.