Harkness Memorial State Park in Waterford, Connecticut, preserves a 304-acre Long Island Sound estate centered on Eolia, a 42-room Renaissance Revival mansion set amid formal gardens and greenhouses. The summer home of philanthropists Edward and Mary Harkness, the estate grew from a mansion designed by Lord & Hewlett and built in 1906–07, with later additions including a carriage house and water tower by James Gamble Rogers. Between 1918 and 1929, Beatrix Jones Farrand shaped the grounds into the formal landscape that defines the property. Mary Harkness gave the estate to Connecticut in 1950; it joined the state park system in 1952 and was listed on the National Register in 1986.