Major professional sports leagues in the United States and Canada
The Canadian Football League is the highest level of play in Canadian football. The league was organized in 1956 as a cooperative agreement between two regional leagues, the Big Four (which dated to 1907) and the WIFU (which was founded in 1936), and became independent from Football Canada in 1958. The league now consists of nine teams, all based in Canada. The Grey Cup is awarded annually to the champion every November and is the highest attended sporting event in the nation. The oldest extant teams, the Hamilton Tiger-Cats and the Toronto Argonauts, trace their origins to the late 1860s and early 1870s, which ranks them amongst the oldest professional sports teams of any kind still in existence on the continent. The CFL attempted an expansion into the United States in cities that had no NFL team between 1993 and 1995, though the expansion teams all either folded or relocated to Canadian cities.
List of defunct American and Canadian professional football teams
For the sake of simplicity, this list will only focus on national (non-regional, non-National Football League) outdoor North American football teams not covered in other lists (i.e. the All-America Football Conference, the first three universally recognized as major incarnations of the American Football League, Continental Football League, World Football League, American Football Association, United States Football League, non-European teams from the World League of American Football, Canadian Football League (including predecessors and South Division teams), and the XFL). As a general rule, only teams with existing Wikipedia articles are listed here.