The end zones were invented as a result of the creation of the forward pass. Prior to this, the goal line and end line were the same, and players scored a touchdown by leaving the field of play through that line. Goal posts were placed on the goal line, and any kicks that did not result in field goals but left the field through the end lines were simply recorded as touchbacks (or, in the Canadian game, ; it was during the pre-end zone era that Hugh Gall set the record for most singles in a game, with eight).
In the earliest days of the forward pass, the pass had to be caught in-bounds and could not be thrown across the goal line (as the receiver would be out of bounds). This also made it difficult to pass the ball when very close to one's own goal line, since merely dropping back to pass or kick would result in a (rules of the forward pass at the time required the passer to be five yards behind the line of scrimmage, which would make throwing the forward pass when the ball was snapped from behind one's own five-yard line illegal in itself).
Thus, in 1912, the end zone was introduced in . In an era when professional football was still in its early years and dominated the game, the resulting enlargement of the field was constrained by fact that many college teams were already playing in well-developed stadiums, complete with stands and other structures at the ends of the fields, thereby making any substantial enlargement of the field unfeasible at many schools. Eventually, a compromise was reached: 12 yards of end zone were added to each end of the field, but in return, the playing field was shortened from 110 yards to 100, resulting in the physical size of the field being only slightly longer than before. Goal posts were originally kept on the goal lines, but after they began to interfere with play, they moved back to the end lines in 1927, where they have remained in college football ever since. The National Football League moved the goal posts up to the goal line again in 1933, then back again to the end line in 1974.
As with many other aspects of gridiron football, adopted the forward pass and end zones much later than American football. The forward pass and end zones were adopted in 1929. In Canada, college football never reached a level of prominence comparable to U.S. college football, and professional football was still in its infancy in the 1920s. As a result, Canadian football was still being played in rudimentary facilities in the late 1920s. A further consideration was that the (the governing body of Canadian football at the time) wanted to reduce the prominence of single points (then called rouges) in the game. Therefore, the CRU simply appended 25-yard end zones to the ends of the existing 110-yard field, creating a much larger field of play. Since moving the goal posts back 25 yards would have made the scoring of field goals excessively difficult, and since the CRU did not want to reduce the prominence of field goals, the goal posts were left on the goal line where they remain today. However, the rules governing the scoring of singles were changed: teams were required to either kick the ball out of bounds through the end zone or force the opposition to down a kicked ball in their own end zone in order to be awarded a point. By 1986, at which point CFL stadiums were becoming bigger and comparable in development to their American counterparts in an effort to stay financially competitive, the CFL reduced the depth of the end zone to 20 yards.