The US Open Tennis Championship, commonly known as the US Open and originally founded as the U.S. National Championship in 1881, is the final Grand Slam tennis tournament of the year. Organized by the USTA, this annual two-week event is held each late August and early September on the hard courts of the Billie Jean King National Tennis Center in Flushing Meadows, New York. It features men’s and women’s singles, doubles, mixed doubles, and junior and wheelchair competitions.