The Mansion House, constructed in stages between 1861 and 1914, was the home of the 19th century utopian Oneida Community which lasted from 1848 -1880. It is a National Historic Landmark open to the public for guided tours, meals and overnight lodging.

The 93,000 sq. ft., three-story brick structure houses a museum, 37 apartments, 9 guestrooms, a dining room and a 300-seat hall, and is surrounded by 14 acres of lawns and gardens.