is a men's professional soccer league sanctioned by the United States Soccer Federation which represents the sport's highest level in the United States. The league comprises 24 teams—21 in the U.S. and 3 in Canada and constitutes one of the major professional sports leagues in both countries. The regular season runs from March to October, with each team playing 34 games; the team with the best record is awarded the Supporters' Shield. Fourteen teams compete in the postseason MLS Cup Playoffs through October and November, culminating in the championship game, the MLS Cup. MLS teams also play in domestic competitions against teams from other divisions in the U.S. Open Cup and in the Canadian Championship. MLS teams also compete against continental rivals in the CONCACAF Champions League. The league plans to expand to 27 teams with the addition of Inter Miami CF and Nashville SC in 2020 and Austin FC in 2021, with further plans to expand to 28 teams by 2022 and 30 teams at a later date.
With an average attendance of over 20,000 per game, MLS has the third highest average attendance of any sports league in the U.S. after the National Football League (NFL) and Major League Baseball(MLB), and is the seventh highest attended professional soccer league worldwide.