A nine-member Board of Managers was created and appointed to initiate and oversee construction of the actual building. They chose architect Frederick Clarke Withers to design a building according to the Kirkbride Plan, then a popular theory for the design of mental institutions. Withers planned a building 1,500 feet (457 m) in length and over 500,000 square feet (45,000 m2) in area, most of it two wings that would house patients. It was the first institutional building in the U.S. designed in the High Victorian Gothic style. Calvert Vaux and Frederick Law Olmsted, designers of New York's Central Park, laid out the surrounding landscape. Like Withers, they had been mentored by the influential Andrew Jackson Downing in nearby Newburgh.