The National Hockey League (NHL; French: Ligue nationale de hockey—LNH) is a professional ice hockey league composed of 30 member clubs: 23 in the United States and 7 in Canada. Headquartered in New York City, the NHL is widely considered to be the premier professional ice hockey league in the world,^[2] and one of the major professional sports leagues in the United States and Canada. The Stanley Cup, the oldest professional sports trophy in North America,^[3] is awarded annually to the league playoff champion at the end of each season.

The National Hockey League was organized on November 26, 1917, in Montreal, Quebec, after the suspension of operations of its predecessor organization, the National Hockey Association (NHA), which had been founded in 1909 in Renfrew Ontario.^[4] The NHL immediately took the NHA's place as one of the leagues that contested for the Stanley Cup in an annual interleague competition before a series of league mergers and folds left the NHL as the only league left competing for the Stanley Cup in 1926. The NHL started with four teams (all based in Canada) and, through a series of expansions, contractions and relocations, is now composed of 30 active franchises. The "nation" referred to by the league's name was Canada, although the league has now been binational since 1924 when its first team in the United States, the Boston Bruins, began play. After a labour-management dispute that led to the cancellation of the entire 2004–05 season, the league resumed play under a new collective agreement that included a salary cap. In 2009, the NHL enjoyed record highs in terms of sponsorships, attendance, and television audiences.^[5]

The league draws many highly skilled players from all over the world and currently has players from approximately 20 different countries.^[6] Canadians have historically constituted the majority of the players in the league, with a dramatically increasing percentage of American and European players in recent seasons.The National Hockey League was established in 1917 as the successor to the National Hockey Association (NHA), officially called the National Hockey Association of Canada Limited. Founded by Ambrose O'Brien in 1909, the NHAbegan play one year later with seven teams in Ontario and Quebec, and was one of the first major leagues in professional ice hockey. But by the NHA's eighth season, a series of disputes with Toronto Blueshirts owner Eddie Livingstone led the other team owners, representing the Montreal Canadiens, Montreal Wanderers, Ottawa Senators, and Quebec Bulldogs to meet at the Windsor Hotel in Montreal to talk about the league's future.^[8] Realizing the league constitution left them unable to force Livingstone out, the four teams voted instead to suspend the NHA, and on November 26, 1917, formed the National Hockey League.^[9] While a full member of the new league, the Bulldogs were unable to play, and the remaining owners created a new team in Toronto, the Arenas, to compete with the Canadiens, Wanderers and Senators.^[10] The first games were played three weeks later on December 19.^[11]Joe Malone scored five goals in a 7–4 victory for the Canadiens over the Senators on opening night; he finished the 1917–18 season with 44 goals in 20 games.^[12] The league nearly collapsed in January 1918 when the Montreal Arena burned down, causing the Wanderers to cease operations and forcing the Canadiens to hastily find a new arena.^[13] The NHL continued on as a three-team league until the Bulldogs returned in 1919.^[14]

The NHL replaced the NHA as one of the leagues that competed for the Stanley Cup, which was an interleague competition back then. Toronto won the first NHL title, then defeated the Pacific Coast

Hockey Association's Vancouver Millionaires to win the 1918 Stanley Cup^[15] The Canadiens won the league title in 1919; however their Stanley Cup Final against the Seattle Metropolitans was abandoned with the series tied after several players became ill as a result of the Spanish Flu epidemic that resulted in Montreal defenceman Joe Hall's death.^[16] Montreal defeated the Calgary Tigers of the Western Canada Hockey League (WCHL) in 1924 to win their first Stanley Cup as a member of the NHL.^[17] The Hamilton Tigers, who had relocated from Quebec in 1920, won the regular season title in 1924–25 but refused to play in the championship series unless they were given a C$200 bonus.^[18] The league refused and declared the Canadiens the league champion after they defeated the Toronto St. Patricks (formerly the Arenas) in the semi-final. Montreal was then defeated by the Victoria Cougars for the 1925 Stanley Cup. It was the last time a non-NHL team won the trophy,^[19] as the Stanley Cup became the de facto NHL championship in 1926 after the WCHL ceased operation.[20]