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American football

American football (referred to simply as football in the United States and Canada), also known as gridiron football,[nb 1] is a team sport played by two teams of eleven players on a rectangular field with goalposts at each end. The offense, the team with possession of the oval-shaped football, attempts to advance down the field by running with the ball or throwing it, while the defense, the team without possession of the ball, aims to stop the offense's advance and to take control of the ball for themselves. The offense must advance at least ten yards in four downs or plays; if they fail, they turn over the football to the defense, but if they succeed, they are given a new set of four downs to continue the drive. A game is won by the team with the higher number of points, which are scored primarily by advancing the ball into the opposing team's end zone for a touchdown or kicking the ball through the opponent's goalposts for a field goal.

This article is about the American variation of gridiron football. For other uses, see American football (disambiguation).

Highest governing body

International Federation of American Football

November 6, 1869
New Brunswick, New Jersey, United States
(Princeton vs. Rutgers)

Full

11 (both teams may freely substitute players between downs)

Football field (rectangular: 120 yards long, 53+1⁄3 yards wide)

Glossary of American football

Worldwide (most popular in North America)

Demonstrated at the 1904 and 1932 Summer Olympics, flag football at the 2028 Summer Olympics

Invitational sport at 2005, 2017, and 2022 (flag football) Games

American football evolved in the United States, originating from the sports of soccer and rugby. The first American football match was played on November 6, 1869, between two college teams, Rutgers and Princeton, using rules based on the rules of soccer at the time. A set of rule changes drawn up from 1880 onward by Walter Camp, the "Father of American Football", established the snap, the line of scrimmage, 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. The sport is closely related to Canadian football, which evolved in parallel with and at the same time as the American game, although its rules were developed independently from those of Camp. Most of the features that distinguish American football from rugby and soccer are also present in Canadian football. The two sports are considered the primary variants of gridiron football.


American football is the most popular sport in the United States in terms of broadcast viewership audience. 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 2022, nearly 1.04 million high-school athletes play the sport in the U.S., with another 81,000 college athletes in the NCAA and the NAIA.[3] The National Football League (NFL) 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 globally. In 2022, the league had an annual revenue of around $18.6 billion,[4] making it the most valuable sports league in the world.[5] Other professional and amateur leagues exist worldwide, but the sport does not have the international popularity of other American sports like baseball or basketball; the sport maintains a growing following in the rest of North America, Europe, Brazil, and Japan.

The referee is positioned behind and to the side of the offensive backs. The referee is charged with oversight and control of the game and is the authority on the score, the down number, and any rule interpretations in discussions among the other officials. The referee announces all penalties and discusses the infraction with the offending team's captain, monitors for illegal hits against the quarterback, makes requests for first-down measurements, and notifies the head coach whenever a player is ejected. The referee positions themselves to the passing arm side of the quarterback. In most games, the referee is responsible for spotting the football prior to a play from scrimmage.

The umpire is positioned in the defensive backfield, except in the NFL, where the umpire is positioned lateral to the referee on the opposite side of the formation. The umpire watches play along the line of scrimmage to make sure that no more than 11 offensive players are on the field before the snap, and that no offensive linemen are on pass plays. The umpire monitors contact between offensive and defensive linemen and calls most of the holding penalties. The umpire records the number of timeouts taken and the winner of the coin toss and game score. They also assist the referee in situations involving possession of the ball close to the line of scrimmage, determines whether player equipment is legal, and dries wet balls prior to the snap if a game is played in rain.

illegally downfield

The back judge is positioned deep in the defensive backfield, behind the umpire. The back judge ensures that the defensive team has no more than 11 players on the field and determines whether catches are legal, whether field goal or extra point attempts are good, and whether a violation occurred. The back judge is also responsible for the play clock, the time between each play, when a visible play clock is not used.

pass interference

The head linesman/down judge is positioned on one end of the line of scrimmage. The head linesman/down judge watches for any line-of-scrimmage and illegal use-of-hands violations and assists the line judge with illegal shift or illegal motion calls. The head linesman/down judge also rules on out-of-bounds calls that happen on their side of the field, oversees the chain crew, and marks the forward progress of a runner when a play has been whistled dead.

The side judge is positioned twenty yards downfield of the head linesman. The side judge mainly duplicates the functions of the field judge. On field goal and extra point attempts, the side judge is positioned lateral to the umpire.

The line judge is positioned on the end of the line of scrimmage, opposite the head linesman. They supervise player substitutions, the line of scrimmage during punts, and game timing. The line judge notifies the referee when time has expired at the end of a quarter and notifies the head coach of the home team when five minutes remain for halftime. In the NFL, the line judge also alerts the referee when . If the clock malfunctions or becomes inoperable, the line judge becomes the official timekeeper.

two minutes remain in the half

The field judge is positioned twenty yards downfield from the line judge. The field judge monitors and controls the , counts the number of defensive players on the field, and watches for offensive pass interference and illegal use-of-hands violations by offensive players. The field judge also makes decisions regarding catches, recoveries, the ball spot when a player goes out of bounds, and illegal touching of fumbled balls that have crossed the line of scrimmage. On field goal and extra point attempts, the field judge is stationed under the upright opposite the back judge.

play clock

The center judge is an eighth official used only in the top level of college football. The center judge stands lateral to the referee, the same way the umpire does in the NFL. The center judge is responsible for spotting the football after each play and has many of the same responsibilities as the referee, except announcing penalties.

, edited by John Schulian; 2014 (New York: Library of America; ISBN 978-1598533071).

Football: Great Writing About the National Sport

at Curlie

American football

National Football League

International Federation of American Football

NFL 360, an introductory website to football rules

Excerpts of a 1903 football game between the University of Chicago and University of Michigan