The six teams are the Boston Bruins, Chicago Black Hawks,[a] Detroit Red Wings, Montreal Canadiens, New York Rangers, and Toronto Maple Leafs.
The NHL consisted of 10 teams during the 1920s, but the league experienced a period of retrenchment during the Great Depression, losing the Pittsburgh Pirates/Philadelphia Quakers, Ottawa Senators/St.
Despite various outside efforts to initiate expansion after the war, including attempted revivals of the Maroons and Americans franchises, the league's membership remained at six teams for the next 25 seasons.
The next longest streak, from the 2000 expansion to Saint Paul, Minnesota, and Columbus, Ohio, to the 2011 move of the Atlanta Thrashers to Winnipeg, is not even half as long; only two other periods (1982–1991 and 2011–2017) lasted longer than five seasons.
The league had a rule that gave each team exclusive rights to negotiate contracts with promising local players within 50 miles (80 kilometres) of its home ice.
The league boasted a small amount of good American players during the 1940s including the All-Star goalkeepers Frank Brimsek and Mike Karakas, defenceman John Mariucci, and forward Cully Dahlstrom.
At the beginning of the Original Six era, the Chicago Black Hawks were owned by Major Frederic McLaughlin, a fiercely patriotic man who tried to stock his roster with as many American players as possible.
The Canadiens' only American-born skater was Norm Dussault, a forward who was born in Springfield, Massachusetts, but grew up in Sherbrooke, Quebec.
At one point, for instance, Red Wings owner James E. Norris effectively owned the Black Hawks as well and was also the largest stockholder in the Rangers.
[13] He also had significant influence over the Bruins by way of mortgages extended to the team to help keep it afloat during the Great Depression, which led some critics to joke that NHL stood for "Norris House League.
The stark labor conditions led to several players' disputes, including a 1957 antitrust action and attempted union formation; the owners' control was further visible when four-time Stanley Cup champion and Red Wings forward Ted Lindsay, a main force agitating for a players' union in 1957, was sent to the last-place Black Hawks.
Subsequent actions in the early 1960s by Toronto players Bob Baun and Carl Brewer finally led to the 1967 formation of the National Hockey League Players' Association (NHLPA), though inaugural NHLPA executive director Alan Eagleson continued to obfuscate the pension's financials while he skimmed money from the plan, exposed only in 1989.
In 1965, the league decided to double in size by adding six teams, and in February 1966, expansion franchises were awarded to Los Angeles, Minnesota, Philadelphia, Pittsburgh, St. Louis, and the San Francisco–Oakland area.
The first dozen seasons (1967–68 to 1978–79) of the expansion era saw the continued dominance by Original Six teams, including the Bobby Orr-led Bruins in the early 1970s and the Canadiens' dynasty at the end of that decade.
Also, the 1991–92 Pittsburgh Penguins are the only team to also win the Cup after beating three of the Original Six (New York and Boston in the Wales Conference playoffs, and Chicago in the finals).
The final active player and official in any on-ice capacity for the league was linesman John D'Amico, who retired at the end of the 1986–87 season.