The National Football League (NFL) is the largest professional American football league in the world. It is an unincorporated association controlled by its members. It was formed by eleven teams in 1920 as the American Professional Football Association (the league changed the name to American Professional Football League in 1921 and then settled on its current name in 1922).

The league currently consists of thirty-two teams from American cities and regions, divided evenly into two conferences — the American Football Conference (AFC) and National Football Conference (NFC) — of four four-team divisions.

The regular season is a seventeen-week schedule during which each team has one bye week and plays sixteen games. This schedule includes six games against a team's divisional rivals, as well as several inter-division and inter-conference games. The season currently starts on the Thursday night in the first full week of September (the Thursday after Labor Day) and runs weekly to late December or early January.

At the end of each regular season, six teams from each conference play in the NFL playoffs, a twelve-team single-elimination tournament that culminates with the championship game, known as the Super Bowl. This game is held at a pre-selected site which is usually a city that hosts an NFL team.

--SOURCE: WIKIPEDIA.ORG