The US Open women's singles championship is an annual tennis event that is being held since 1887 as part of the US Open tournament. The tournament is played on outdoor hard courts at the USTA Billie Jean King National Tennis Center in Flushing Meadows – Corona Park, New York City. The US Open is played during a two-week period in late August and early September and has been chronologically the last of the four Grand Slam tournaments of the tennis year since 1987. The Philadelphia Cricket Club (1887–1920) and Forest Hills (1921–1977) hosted the event before it settled in 1978 at its current site. The United States Tennis Association is the national body that organizes this event. The champion receives a full-size replica of the event's trophy engraved with her name. In 2022, the winner received prize money of US$2,600,000. History The format of the women's singles event has undergone several changes since the first edition. From 1888 through 1918, the event started with a knockout phase, the All-Comers singles, whose winner faced the defending champion in a challenge round. The All-Comers winner was awarded the title by default six times (1893, 1899, 1900, 1905, 1906 and 1907) in the absence of the previous year's champion. The challenge round system was abolished with the 1919 edition. Since 1887, all matches have been played as the best-of-three sets, except in the eleven-year period from 1891 until 1901, when the challenge round was scored the best-of-five-sets. From 1894 until 1901 the women were required to play best-of-five sets in both the all-comers final and the challenge round. Format Since 1887, the winner of the next game at five-games–all took the set in every match except the All-Comers final and the challenge round, which was won by the player who had won at least six games and at least two games more than his opponent. This advantage format was introduced for the final sets of early rounds, for women starting in 1887, and used for all sets in final rounds from 1887 through 1969. The tie-break system was introduced in 1970 for all sets, in its best-of-nine points sudden death version until 1974, and in its best-of-12 points lingering death version since 1975. The US Open is the only Grand Slam tournament to have a third set tie-break, which has occurred twice in women's singles finals in 1981 and in 1985. Surface The