Before the 2016 season, the NCAA required that a conference have a minimum of 12 teams and play in two divisions in order to hold a football championship game that did not count against the limit of 12 regular-season games per team.
Twelve-team conferences
The first post-regular season conference championship game played in Division I-A football was the 1992 SEC Championship Game, won by Alabama over Florida. The SEC had gone from being a 10-team conference in 1991, to being a 12-team conference—divided into two six-team divisions—in 1992. The next championship games to debut were that of the Big 12 Conference and Western Athletic Conference, starting in 1996. That year, the Big Eight Conference and Southwest Conference dissolved and were essentially replaced by the Big 12, with 12 teams divided into six-team divisions; while the WAC expanded to 16 teams, divided into eight-team divisions. This was followed in 1997 by the Mid-American Conference, which expanded from 10 to 12 teams, divided into six-team divisions. In 1999, the WAC contracted to eight teams and discontinued its championship games. New championship games were next added in 2005, when both the Atlantic Coast Conference and Conference USA expanded from 11 teams to 12 teams and implemented six-team divisions. The requirement for a conference to have 12 teams in order to stage a championship game resulted in the Big 12 halting its championship game after the 2010 season, as the conference contracted to 10 members in 2011. In 2011, the Big Ten Conference added its 12th team, split into six-team divisions, and added a championship game. That same season, what had been the Pacific-10 Conference added two teams, split into six-team divisions, renamed itself the Pac-12 Conference, and initiated its own championship game. The Mountain West Conference grew to 12 teams in 2013, as did the American Athletic Conference in 2015; both structured themselves into six-team divisions and began staging championship games.
Smaller conferences
At the conclusion of the 2015 season, only the Big 12 and the Sun Belt Conference did not have championship games, as neither conference had the required minimum of 12 teams. In January 2016, the NCAA approved championship games for smaller conferences, provided the championship game features either the top two teams at the end of a full round-robin conference schedule, or the winners of each of two divisions, with each team playing a full round-robin schedule within its division. Following that change to NCAA rules, the Big 12 reinstated its championship game in 2017, operating with 10 teams in a single division while playing a full round-robin schedule. In 2017, the Sun Belt Conference grew to 12 members with the addition of Coastal Carolina. At that time, the Sun Belt operated with all teams in a single division but did not play a full round-robin schedule, thus did not hold a championship game. The conference contacted to 10 football members after the memberships of Idaho and New Mexico State were not extended following the 2017 season. The conference announced that it would begin playing a championship game in 2018, which it facilitated by splitting into two five-team divisions. Thus, 2018 was the first season that all FBS conferences held a championship game.
