The W.W. Mayo House is the home of the founders of both the Mayo Clinic and the Green Giant Company. Dr. Mayo hand-built the Gothic-style home in 1859 and set up his first medical practice in a room upstairs. Later the Cosgrove family, founders of Green Giant, lived there. The site is located at 118 N. Main St. in downtown Le Sueur. The W.W. Mayo House is managed by the Ney Nature Center.