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 lead-up of events to the last Grand Slam
tournament of the season, the US Open. The women's event was first held in 2011 in College Park,
Maryland as the Citi Open, and for the 2012 season, the ATP and the WTA decided to merge their
Maryland and Washington spots into a men and women joint tournament.