<P> American football evolved in the United States, originating from the sports of association football and rugby football . The first match of American football was played on November 6, 1869, between two college teams, Rutgers and Princeton, under rules based on the association football rules of the time . During the latter half of the 1870s, colleges playing association football switched to the Rugby Union code, which allowed carrying the ball . A set of rule changes drawn up from 1880 onward by Walter Camp, the "Father of American Football", established the snap, eleven - player teams, and the concept of downs; later rule changes legalized the forward pass, created the neutral zone, and specified the size and shape of the football . </P> <P> American football as a whole is the most popular sport in the United States . The most popular forms of the game are professional and college football, with the other major levels being high school and youth football . As of 2012, nearly 1.1 million high school athletes and 70,000 college athletes play the sport in the United States annually, almost all of them men, with a few exceptions . The National Football League, the most popular American football league, has the highest average attendance of any professional sports league in the world; its championship game, the Super Bowl, ranks among the most - watched club sporting events in the world, and the league has an annual revenue of around US $10 billion . </P> <P> In the United States, American Football is called "football ." The terms "gridiron" or "American football" are favored in English - speaking countries where other codes of football are popular, such as the United Kingdom, Ireland, New Zealand, and Australia . </P> <Table> <Tr> <Td> Part of the American football series on History of American football </Td> </Tr> <Tr> <Td> <P> Origins of American football </P> <Dl> <Dd> Early history of American football </Dd> <Dd> First game </Dd> <Dd> Walter Camp </Dd> <Dd> First pro player </Dd> <Dd> First pro league </Dd> <Dd> Modern history of American football </Dd> </Dl> <P> Close relations: </P> <Dl> <Dd> Medieval football </Dd> <Dd> Old division football </Dd> <Dd> Rugby football </Dd> <Dd> Association football </Dd> <Dd> Canadian football </Dd> </Dl> <P> Black players in professional American football Homosexuality in American football Concussions in American football Rugby union comparison Rugby league comparison Canadian football comparison Pro Football Hall of Fame College Football Hall of Fame Years in American football </P> <Dl> <Dd> NFL season - by - season </Dd> <Dd> College football season - by - season </Dd> <Dd> Glossary of American football </Dd> </Dl> </Td> </Tr> <Tr> <Td> American football Portal <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> </Table>

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