History of the NFL

1920 First season of American Professional Football Association (APFA) featured 14 teams from four states, all of whom existed in some form as participants of regional leagues in their respective territories. Only 2 of them are still in the league. The list of the teams were: Akron Pros, Buffalo All-Americans, Canton Bulldogs, Chicago Cardinals (Arizona Cardinals), Chicago Tigers, Cleveland Tigers, Columbus Panhandles, Dayton Triangles, Decatur Staleys (Chicago Bears), Detroit Heralds, Hammond Pros, Muncie Flyers, Rochester Jeffersons, Rock Island Independents.

1921 Green Bay Packers joined the NFL. Decatur Staleys relocated to Chicago to became Chicago Bears.

1922 The APFA took on its current name NFl.

1925 New York Giants joined the NFL.

1930 Portsmouth Spartans (Detroit Lions since 1934) joined the NFL.

1932 Boston Braves (Washington Redskins from 1937 to 2019, Washington Football Team from 2020 to 2021, Washington Commanders since 2022) joined the NFL.

1933 Philadelphia Eagles and Pittsburgh Steelers joined the League. The first official NFL championship game took place on December 17. The Chicago Bears defeated the New York Giants 23–21 at Wrigley Field in Chicago before an estimated crowd of 25,000 fans.

1937 Cleveland Rams (Los Angeles Rams from 1946 to 1994 and since 2016, St. Louis Rams from 1995 to 2015, ) joined the NFL.

1944 The All-America Football Conference (AAFC) was founded by Chicago Tribune sports editor Arch Ward on June 4. One of the NFL's most formidable challengers, the AAFC attracted many of the nation's best players, and introduced many lasting innovations to the game. However, the AAFC was ultimately unable to sustain itself in competition with the NFL.

1949 Three AAFC teams were admitted to the NFL: Cleveland Browns, San Francisco 49ers, Baltimore Colts. The last team played only 1 season before financial issues caused them to fold.

1953 Baltimore Colts (Indianapolis Colts since 1984) joined the NFL.

1960 First season of American Football League (AFL) featured 8 teams. The list of the teams were: Boston Patriots (New England Patriots since 1971), Buffalo Bills, Dallas Texans (Kansas City Chiefs since 1963), Denver Broncos, Houston Oilers (Tennessee Oilers from 1997 to 1998, Tennessee Titans since 1999), Los Angeles Chargers (San Diego Chargers from 1961 to 2016), Titans of New York (New York Jets since 1963) and Oakland Raiders (Los Angeles Raiders from 1982 to 1994, Oakland Raiders from 1995 to 2019, Las Vegas Raiders since 2020). Also this year Dallas Cowboys joined the NFL.

1961 Minnesota Vikings joined the NFL.

1966 Atlanta Falcons and Miami Dolphins joined the AFL. On June 8, the collaborators from NFL and AFL announced a merger agreement in New York.

1967 The first Super Bowl (AFL–NFL World Championship Game before) took place on January 15. The Green Bay Packers defeated the Kansas City Chiefs 35–10 at the Los Angeles Memorial Coliseum in Los Angeles before an crowd of 61,946 fans. New Orleans Saints joined the NFL.

1968 Cincinnati Bengals joined the AFL.

1970 The leagues fully merged under the name National Football League and divided into two conferences of an equal number of teams. Since the pre-merger NFL had six more teams than the AFL, three NFL teams – the Pittsburgh Steelers, Cleveland Browns and Baltimore Colts (Indianapolis Colts) – moved to the AFC, the conference containing the AFL teams.

1976 Seattle Seahawks and Tampa Bay Buccaneers joined the NFL.

1995 Carolina Panthers and Jacksonville Jaguars joined the NFL.

1996 Baltimore Ravens joined the NFL.

2002 Houston Texans joined the NFL.