Question: how many square feet is the vanderbilt mansion?
Answer: Biltmore House, the main residence, is a Châteauesque-style mansion built for George Washington Vanderbilt II between 1889 and 1895 and is the largest privately owned house in the United States, at 178,926 square feet (16,622.8 m2) of floor space (135,280 square feet of living area).