Brentwood State Park occupies land that was once part of the Pilgrim Psychiatric Center. As that facility underwent downsizing in the late 1990s and early 2000s, a 460-acre (1.9 km2) portion of the property was purchased for redevelopment as residential and business space. The developer transferred 52 acres (0.21 km2) to the New York State Office of Parks, Recreation and Historic Preservation to be converted into athletic fields.[3]