Perched atop the sun-bathed hill of the estate known as “Sonnenberg” (German for “sunny hill”) is a 40-room Queen Anne-style mansion. New York City bank financier Frederick Ferris Thompson and his wife, Mary Clark Thompson, the daughter of New York State governor Myron Holley Clark, purchased the property in 1863 when it featured just a brick farmhouse on 14 acres.
As business prospered, the couple purchased additional acreage and replaced the farmhouse with the mansion, which was built between 1885-1887. Today, visitors can view many of its stately rooms, including the impressive Great Hall, the Billiard and Trophy Rooms, the Library, Drawing Room, Dining Room, and upstairs, the Master Bedroom and several additional guest rooms.
The Mansion is handicap-accessible throughout the first floor. A number of special events throughout the Garden Season are hosted on the wide porches of the Veranda, which encircles the south and west sides of the Mansion. A 2009-2010 restoration project restored the historic masonry and foundation supporting this heavily-used public event venue.