The league was formed in 1917 in Montreal, Quebec, Canada from a predecessor organization, the National Hockey Association (NHA), founded in 1909. It started with four teams, and through a series of expansions, contractions and relocations, the league is now composed of 30 teams, 24 of which are based in the United States and six in Canada.

After a labour dispute that led to the cancellation of the entire 2004–05 season, the league has staged a successful comeback, including revenue and profit growth.