Major professional sports leagues in the United States and Canada
The major professional sports leagues in the United States and Canada are the highest men's competitions of team sports in those countries. The four leagues traditionally included in the definition are Major League Baseball (MLB), the National Basketball Association (NBA), the National Football League (NFL), and the National Hockey League (NHL). Other prominent leagues include Major League Soccer (MLS) and the Canadian Football League (CFL).
MLB, NBA, NFL, and 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 English Premier League they make up the top five sports leagues by revenue in the world. In addition, the sports of these four leagues were all developed in their modern forms in North America, and all except American football have become popular internationally. Because the leagues enjoy a significant place in popular culture in the U.S. and Canada, the best players from these leagues often become cultural icons in both countries.
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 2018. The two indoor leagues, the NHL and NBA, play in arenas that average under 19,000 seats, resulting in the CFL holding the third highest average attendance of the six leagues, at close to 24,000 per game, after the NFL and MLB.
The Big Four leagues currently have 30–32 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, North American 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. Teams do not leave the league unless they are disbanded (which has not happened since 1954) or merged with another team (which has not happened since 1978). Relocation can change the name of a team, but it is generally still considered to be the same entity.
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 (or association football) was first professionalized in 1894, but leagues suffered greatly from lack of sustainability and seldom lasted more than a decade. The sport's greatest successes were in the form of the American Soccer League (1921–1933) (ASL), the original North American Soccer League (1968–1984) (NASL), and Major League Soccer (MLS) since 1996.
The term "major league" is usually limited to professional team sports. Individual professional sports competitions such as PGA Tour golf and NASCAR Cup Series auto racing are also very popular and serve as those sports' most prominent competitions with levels of media coverage, competition, and fan following comparable to the major professional team sports. Amateur competitions such as college football and college basketball, at the upper echelons, also enjoy strong media coverage and fan followings but are generally recognized as inferior to the major professional leagues in level of play because of the inherent limits of the amateur sports system.