| 1920 | A national football organization is formed | Fourteen teams made up the American Professional Football Association. Teams were charged a $100 fee, and there were fourteen teams total. |
| 1922 | The National Football League is born | After two years as the American Professional Football Association, the organization went through a big change. They were renamed the National Football League, or the NFL. |
| 1926 | The NFL hits a growth spurt | The NFL spent several years bouncing back and forth between fourteen and twenty-one teams. In 1926, they at last hit a peak of twenty-two teams—a number they wouldn't surpass until the 1960's. |
| 1931 | The Great Depression hits | Due to the hardships caused by the Great Depression, many teams in the NFL were forced to close down. The league dropped from a high of twenty-two teams in 1926 to only ten teams in 1931. |
| 1932 | A national championship playoff | Despite the depression, the teams within the NFL decided to hold the first ever playoff game when two teams tied for first place. The playoff was played between the Chicago Bears and the Portsmouth Spartans, and the Bears won. |
| 1933 | Segregation | Washington Redskins owner George Marshall proposed a de facto, or a policy, of total racial segregation. The NFL conceded, and black athletes were denied the ability to play for several years. |
| 1939 | The NFL hits television | The first televised NFL game was shown on NBC. The game was played between the Brooklyn Dodgers and the Philadelphia Eagles. |
| 1946 | The NFL moves westward | The teams in the NFL had been stationed from the Midwest to the eastern coast. When the Cleveland Rams relocated to Los Angeles, California, the NFL reached the West Coast for the first time. |
| 1946 | Segregation ends | When the Rams moved to California, they signed African-American players Kenny Washington and Woody Strode. The move ended the segregation within the NFL. |
| 1950 | Changes within the leagues | The league continued changing when the eastern division teams were placed in the American Conference, and the western division teams were placed in the National Conference. The divisions and conferences would switch names several times over the next few years. |
| 1960 | The formation of the American Football League | The NFL gained a rival operation when the American Football League, or the AFL, formed. They had a total of eight teams. |
| 1967 | A championship game | The first championship game between leagues was played between the American Football League and the National Football League. It was played between the Green Bay Packers of the NFL and the Kansas City Chiefs of the AFL, and it would later be named the Super Bowl. |
| 1970 | A merging of leagues | The NFL and the AFL came to an agreement to merge the leagues. They became the National Football Conference and the American Football Conference. |
| 1977 | Records shatter | During a game between the Minnesota Vikings and Chicago Bears, Bears running back Walter Payton set a new single-game record of 275 yards rushing. It was a record that wouldn't be broken for twenty-three years, but would be followed by many other amazing records. |
| 1987 | Players on strike | The NFL Players Association took the players on strike in hopes of getting players a higher revenue. During the month-long strike, games were played using amateur replacement players until the professional players decided they would rather play football than be on strike. |
| 2006 | Amazing players leave the NFL(2006-2008) | Many amazing records would be set during the 80's, 90's, and beyond. Some of the best NFL players in history would play and retire during this time, including Brett Favre and Jerry Rice. |
