The National Football League makes helmets mandatory.

The National Football League (NFL) is a professional American football league in the United States. Composed of 32 teams, it is divided equally between the American Football Conference (AFC) and the National Football Conference (NFC). The NFL is one of the major professional sports leagues in the United States and Canada and the highest professional level of American football in the world. Each NFL season begins annually with a three-week preseason in August, followed by an 18-week regular season, which runs from early September to early January, with each team playing 17 games and having one bye week. Seven teams from each conference, including the four division winners and three wild card teams, then advance to the playoffs, a single-elimination tournament, which culminates in the Super Bowl, played in early February between the winners of the AFC and NFC championship games. The NFL is headquartered in New York City.