The National Women's Soccer League (NWSL) is the top-level professional women's soccer league in the United States. Founded in 2013, the NWSL is composed of nine teams throughout the U.S. and Canada and is the longest-running professional women's soccer league in the U.S. since the launch of Women's Professional Soccer in 2009. It is the current incarnation of women's soccer in the U.S., as the National Women's Soccer League Players Association (NWSLPA) currently negotiates labor conditions.The league has nine teams from across the United States and Canada, including some of the most popular clubs in the game. The Chicago Red Stars, Portland Thorns FC, Utah Royals FC, North Carolina Courage, Washington Spirit, Seattle Reign, Sky Blue FC, Houston Dash and OL Reign form the current NWSL lineup. Over a dozen of the world's best women's soccer players have been part of the NWSL, including USWNT stars Alex Morgan, Megan Rapinoe, Carli Lloyd, Toby Heath, and Mallory Pugh.The season format for the NWSL is a 26-game regular season, with teams competing for the NWSL Shield, which is the award given to the team that finishes with the most points at the end of the regular season. The top four teams at the end of the regular season advance to the NWSL Playoffs, which is a four-team bracket-style tournament to decide the NWSL champion.In its 8-year history, the NWSL has achieved strong and consistent growth in both viewership and engagement metrics. Since its inception in 2013, the NWSL has seen a steady increase in attendance and viewership for its games both in-person and on various broadcast platforms. In 2020, NWSL set records for total average viewership and a peak audience of more than 1.3 million viewers on one match day.The National Women's Soccer League awards a championship trophy to the winners of the annual playoffs. The NWSL Championship has been won five times by North Carolina Courage, twice by Portland Thorns FC, and once by the Chicago Red Stars in 2019. The Washington Spirit will carry the title into the 2021 season. As the NWSL continues to move ahead, the league looks to expand and form more international partnerships to become one of the top women's soccer leagues in the world.