US Open (tennis)

The United States Open Tennis Championships is a hardcourt tennis tournament which is the modern version of one of the oldest tennis championships in the world, the U.S. National Championship, for which men's singles was first contested in 1881. Since 1987, the US Open has been chronologically the fourth and final tennis major comprising the Grand Slam each year; the other three are the Australian Open, French Open and Wimbledon.

The US Open is held annually, starting on the last Monday in August, and lasting for two weeks into September, with the middle weekend coinciding with the Labor Day holiday. The main tournament consists of five event championships: men's and women's singles, men's and women's doubles, and mixed doubles, with additional tournaments for senior, junior, and wheelchair players. Since 1978, the tournament has been played on acrylic hard courts at the USTA Billie Jean King National Tennis Center in Flushing Meadows–Corona Park, Queens, New York City. The US Open is owned and organized by the United States Tennis Association (USTA), a not-for-profit organization. Net proceeds from ticket sales are used to promote the development of tennis in the United States.

The US Open is the only major that employs tiebreakers in every set of a match. If a match reaches a 6-6 tie in the final set (third set for women, fifth set for men) at the Australian Open, the French Open, or Wimbledon, the match continues until one player wins by two games. The sets played before the last set always employ tiebreakers.