Greystone Park Psychiatric Hospital referred to both the former psychiatric hospital and the historic building that it occupied in Morris Plains, New Jersey. Built in 1876, the facility was built to alleviate overcrowding at the state's only other "lunatic asylum" located in Trenton, New Jersey. Originally built to accommodate 350 people, the facility, having been expanded several times, reached a high of over 7700 patients resulting in unprecedented overcrowding conditions.