Major professional sports leagues in the United States and Canada
Major professional sports leagues in the United States and Canada, which compete in the sports of football, baseball, basketball, ice hockey, and soccer, include the National Football League (NFL), Major League Baseball (MLB), the National Basketball Association (NBA), the National Hockey League (NHL), and Major League Soccer (MLS). The NFL only competes in the United States, with the prominent gridiron football league in Canada being the Canadian Football League (CFL).
MLB, the NBA, the NFL, and the NHL are commonly referred to as the "Big Four". Each of these is the wealthiest professional club competition in its sport worldwide, and along with the Premier League, make up the top five sports leagues by revenue in the world.
Each of the Big Four leagues, as well as MLS and the CFL, averages at least 15,000 fans in attendance per game as of 2024. The NFL has the largest stadiums on average in the world, ranging in capacity from just over 60,000 to almost 100,000 spectators, while MLB ballparks generally hold between 30,000 and 50,000 fans. Venues used primarily by MLS and CFL vary more widely in capacity, from about 20,000 to about 60,000. The two indoor leagues, the NHL and NBA, play mostly in arenas that hold 18,000 to 20,000 seats. Many multi-purpose venues host events in multiple leagues, including: NFL and MLS (5), CFL and MLS (2), MLB and MLS (1), and NBA and NHL (11). MLB and NFL teams frequently shared stadiums in the past, although none currently do. The NFL and MLB also play a limited number of annual games in English Premier League stadiums, and the NFL plays a limited number of annual games in stadiums of Germany's Bundesliga, and less often plays games in stadiums of Mexico's Liga MX, Brazil's Brasileirão,, Spain's La Liga, and the Australian Football League.
The Big Four leagues currently have 30 to 32 teams each, most of which are concentrated in the most populous metropolitan areas of the United States and Canada. Unlike the promotion and relegation systems used in sports leagues in various other regions around the world, American and Canadian sports leagues are closed leagues that maintain the same teams from season-to-season. Expansion of the league usually occurs by adding newly formed teams, though mergers with competing leagues have also occurred.
Baseball, American football, and ice hockey have had professional leagues continuously for over 100 years; early leagues such as the National Association of Professional Base Ball Players, the Ohio League, and the National Hockey Association formed the basis of the modern MLB, NFL, and NHL, respectively. Basketball was invented in 1891, and its first professional league formed in the 1920s. The Basketball Association of America, founded in 1946, formed the basis of the NBA in 1949 and has lasted for over 75 years.
Soccer was first professionalized in 1894, with past American-based leagues including the American Soccer League (1921–1933) (ASL) and the original North American Soccer League (1968–1984) (NASL). Major League Soccer (MLS) was established in 1996.