Mason General Hospital was a psychiatric hospital run by the United States War Department on Long Island during World War II.
The facility consisted of all of the buildings that comprised Edgewood State Hospital and three buildings from Pilgrim State Hospital, in addition to numerous temporary buildings, and was named in honor of Brigadier General Charles Field Mason, who had served in the Army Medical Corps.
The hospital operated between 1944 and 1946, and was used for treating the psychological casualties of the battlefield as well as for other related uses.
During the hospital's brief operation, the controversial documentary film Let There Be Light was shot there by famed filmmaker John Huston. The film showed the steps that shell-shocked soldiers took in their rehabilitation towards a normal life after discharge. However, the film was deemed so potentially controversial that the government kept it hidden from the public until 1981.
After 1946, the War Department handed control of Mason General back to New York State, where Edgewood Hospital was managed by Pilgrim, and the three buildings at Pilgrim that partially comprised Mason, 81, 82, and 83, reverted back to their parent complex. Edgewood ceased operation in 1971 and was demolished in 1989 following years of extensive vandalism and neglect. Buildings 81-83 at Pilgrim, the last surviving remnants of Mason General Hospital, are still in use by Pilgrim today.