The
Cincinnati Open is an annual professional tennis event held in Cincinnati, United States. Due to previous sponsorship, it has also been known as: the Thriftway ATP Championships, the Great American Insurance ATP Championships, the Western & Southern Financial Group Masters and Women's Open and, most recently, the Western & Southern Open. It is played on outdoor hard courts at the Lindner Family Tennis Center in Mason, Ohio, and is held in August. The event started on September 18, 1899, and is the oldest tennis tournament in the United States still played in its original city. It also is the third largest tennis event in the United States, after the US Open and the Indian Wells Masters. It is one of the ATP Masters 1000 tournaments on the ATP Tour, and one of the WTA 1000 tournaments on the WTA Tour.