10. (tie) Harbour Hill (80,000 sq ft)
Harbor Hill was built in 1899 in Roslyn, New York. The main façade was based on François Mansart’s Château de Maisons. The home originally sat on 688 acres of land.
10. Florham (80,000 sq ft)
Trinitarian Creek /wikicommons
Florham was built between 1893-1899 for Florence Adele Vanderbilt and her husband. It has 110 rooms and remains today as the 8th largest house in the United States.
9. Meadow Brook Hall (88,000 sq ft)
Wm. Chris Rowland, II/wikicommons
Meadow Brook Hall is a Tudor revival style mansion in Rochester Hills, Michigan. Built between 1926 and 1929 by the widow of John Francis Dodge, the mansion and the surrounding property were donated to the State of Michigan.
7 (tie). Shadow Lawn (90,000 sq ft)
Shadow Lawn is a 130-room, 19-bath building in West Long Branch, Monmouth County, New Jersey. It was built in 1927 for the president of the F.W. Woolworth Company. It is now a historic listed building and part of Monmouth University.
7. (tie). The Cornelius Vanderbilt II House (90,000 sq ft)
The Cornelius Vanderbilt II House was built in 1883 and is the largest private residence ever built in New York City. It was built for the eldest grandson of Cornelius Vanderbilt, sold in 1926 and subsequently demolished.
5. Winterthur Museum, Garden and Library (96,582 sq ft)
Derek Ramsey /wikicommons
Winterthur Museum in Delaware was the former home of Henry Francis du Pont and was designed in the spirit of 18th and 19th century European country houses. It is situated on 979 acres near Brandywine Creek.
4. Arden House (97,188 sq ft)
Arden House was owned by railroad magnate Edward Henry Harriman and designed in 1905. Harriman only lived in it for a few months before his death in 1909. The house features a music room modelled after a medieval great hall.
3. Whitemarsh Hall (100,000 sq ft)
Whitemarsh Hall was a large estate located in Wyndmoor, Pennsylvania. It was built in 1921 and demolished in 1980. It was the third largest private residence in USA and consisted of 6 stories, 147 rooms and 45 bathrooms.
2. Oheka Castle (109,000 sq ft)
Oheka Castle is located on the North Shore of Long Island, NY. and was the country home of Otto Hermann Kahn. Built between 1914 and 1919, it is the second largest private home in USA, comprising 127 rooms and over 109,000 square feet.
1. Biltmore Estate (135,280 sq ft)
Biltmore Estate was built by George Washington Vanderbilt II between 1889 and 1895 and is the largest privately owned house in the United States. Construction of the main house required the labor of well over 1,000 workers.