The National Women's Soccer League (NWSL) is a professional women's soccer league owned by the teams, and under a management contract with the United States Soccer Federation. At the top of the United States league system, it represents the sport's highest level in the United States. The NWSL was established in 2012 as a successor to Women's Professional Soccer (2007–2012), which was itself the successor to Women's United Soccer Association (2001–2003). The league began play in 2013 with eight teams, four of which were former members of Women's Professional Soccer (Chicago Red Stars, Boston Breakers, Sky Blue FC, Western New York Flash).[1][2][3]