The National Hockey League (NHL) holds outdoor games primarily under three brands: the Heritage Classic, Winter Classic, and Stadium Series.
The Heritage Classic has been infrequently held four times, and has thus far featured match-ups between Canadian teams. The 2003 Heritage Classic between the Edmonton Oilers and Montreal Canadiens was the first outdoor regular season game in NHL history. This led to the annual Winter Classic, held on New Year's Day in the United States, starting with the 2008 game between the Pittsburgh Penguins and the Buffalo Sabres. The NHL then started the Stadium Series in 2014 for additional outdoor games. The number of Stadium series games has since varied per season (four in 2014, two in 2016, and only one each in both 2015 and 2017), and has thus far featured match-ups between American teams.
Prior to 2003, NHL teams had been involved in at least three outdoor exhibitions. Two of these came in the 1950s and were effectively informal scrimmages; in 1954, the Detroit Red Wings visited Marquette Branch Prison and played a match against the prison inmates in a fenced-off, open air ice rink, while in 1956, the Boston Bruins played a game against several local teams in Bay Roberts, Newfoundland. In neither case was a formal game structure maintained or score kept, as the NHL teams hopelessly outmatched the hosts. In 1991, the Los Angeles Kings and New York Rangers played a pre-season game outside Caesars Palace in Las Vegas, in the first officially sanctioned outdoor NHL contest. The NHL's outdoor series have proven wildly popular with fans and have led to numerous attendance records. The 2003 Heritage Classic drew 57,167 fans, a league record that stood until 71,217 fans in Buffalo set another NHL record in the inaugural Winter Classic in 2008. The 2014 Winter Classic, between the Detroit Red Wings and Toronto Maple Leafs drew 105,491 fans, the current NHL record.