Greystone Park Psychiatric was known as the largest contiguous foundation in the United States, from it's opening until the Pentagon was built in 1943. This facility was built in 1848 to relieve overcrowding at nearby Trenton State Hospital. In fact, the 292 of Greystone's initial patients transfered from Trenton. Within 4 short years of opening, Greystone was accomodating 200 patients above capacity. An additional dorm building was constructed and existing dining rooms were turned into dormitories to accomodate the patients.