Which organization runs the US Open tennis tournament annually?

The United States Tennis Association runs the US Open tennis tournament annually.

The USTA is the national governing body for tennis in the United States and organizes the tournament, which is held at the USTA Billie Jean King National Tennis Center in Flushing Meadows–Corona Park, Queens, New York.

The event began in 1881 as the U.S. National Championships. Its organizing body was previously known as the United States National Lawn Tennis Association and later the United States Lawn Tennis Association before adopting the USTA name in 1975.

The ATP and WTA represent and administer professional tours, but they do not run the US Open. The International Tennis Federation governs international tennis and sanctions the Grand Slam framework, while the USTA operates this particular major.