The Washington Open (currently sponsored by Citi bank) is a joint professional tennis tournament played on outdoor hard courts, and held annually in late July at the William H.G. FitzGerald Tennis Center in Rock Creek Park, Washington, D.C., United States. The Citi Open is part of the ATP World Tour 500 series on the Association of Tennis Professionals (ATP) World Tour, and of the WTA International tournaments on the Women's Tennis Association (WTA) Tour. The men's competition is part of the US Open Series, a North American lead-up of events to the last Grand Slam tournament of the season, the US Open, in New York City.