The Welwyn estate also includes woodland and other natural habitats, as well as part of the coast facing north onto Long Island Sound. The mansion is currently used as the Holocaust Memorial and Tolerance Center of Nassau County.
Welwyn was originally the estate of Harold Irving Pratt, an American oil industrialist and philanthropist who was born in 1877, and died at Glen Cove in 1939. Harold Pratt, the owner of Welwyn, was one of the sons of Charles Pratt, who was also an oil industrialist and was the founder of the Pratt Institute in Brooklyn, New York.
Welwyn includes the estate's original Georgian-style mansion, which was built in 1913, and which was designed by Delano & Aldrich.
As a preserve
Welwyn Preserve is owned by Nassau County, New York, and is operated as a public preserve. The preserve includes a butterfly garden, extensive mature woodland, salt marsh and a tidal inlet. Dogs are not allowed in the preserve, in order to safeguard the wildlife.
The mansion of the estate currently houses the museum part of the Holocaust Memorial and Tolerance Center of Nassau County. As of 2014, the museum is open on Mondays to Fridays from 10 am to 4:30 pm, and on Saturdays and Sundays from 12 pm to 4 pm.