The Andrew Carnegie Mansion is located at 2 East 91st Street at Fifth Avenue in Manhattan, New York City, New York. Andrew Carnegie built his mansion in 1903 and lived there until his death in 1919; his wife, Louise, lived there until her death in 1946. The building is now the Cooper-Hewitt, National Design Museum, part of the Smithsonian Institution. The surrounding neighborhood on Manhattan's Upper East Side has come to be called Carnegie Hill. The mansion was named a National Historic Landmark in 1966.