Pilgrim Psychiatric Center, formerly known as Pilgrim State Hospital, is a state-run psychiatric hospital located in Brentwood, New York. Nine months after its official opening in 1931, the hospital's patient population was 2,018. At its peak in 1956, Pilgrim State Hospital could claim to be the largest mental hospital in the U.S., with 14,438 patients.Its size has never been exceeded by any other facility, though it is now far smaller than it once was.