The National Football League (NFL), which was founded in 1920, was preceded by the American Professional Football Association (APFA), which featured ten clubs from four different states and competed in local regional leagues.
The league changed to its current name in 1922. The NFL became the first professional football league to successfully establish a presence on a national basis after several decades of fruitless attempts.
The only two founding teams that are still competing in the league are the Decatur Staleys (now the Chicago Bears) and the Chicago Cardinals (now the Arizona Cardinals).
The Green Bay Acme Packers, established in 1919 (entered the NFL in 1921; currently known as the Green Bay Packers), are the oldest NFL team still operating in the same city.
The Chicago Bears, Chicago Cardinals, Green Bay Packers, New York Giants, Boston Braves (today’s Washington Football Team), and Portsmouth Spartans (today’s Detroit Lions) were the six original teams that competed in the first playoffs, which were held in 1932.
The only two founding teams that are still competing in the league are the Decatur Staleys (now the Chicago Bears) and the Chicago Cardinals (now the Arizona Cardinals).
The Rams, Browns, 49ers, Vikings, Saints, Falcons, Cowboys, and Colts joined the league between 1944 and 1969. Then, in 1969/1970, the NFL and AFL combined, adding 10 new teams.