August Belmont Jr. (February 18, 1853 – December 10, 1924) was an American financier. He financed the construction of the original New York subway (1900-1904) and for many years headed the Interborough Rapid Transit Co., which ran the transit system. August was born in Manhattan and was the grandson of Commodore Matthew Perry.
He founded the Interborough Rapid Transit Company in 1902 to help finance the construction of and operate the first underground subway line. He served as president, and, in 1907, chairman of the company. Belmont holds the distinction of owning the world’s only purpose built private subway car. Named Mineola, it was used by Belmont to give tours of the IRT.
Belmont was involved in World War I and received a commission as major in the United States Army Air Service on November 9, 1917, in France. He also owned thoroughbred and polo horses and was considered the saviour of horse racing in New York State and was the president of the American Kennel Club. The land he owned on Long Island became the Belmont State Park after his death. There is also a horse racing track with his name on it in the greater New York City area.