The Pacific-12 Conference (Pac-12) is a collegiate athletic conference that operates in the Western United States. It participates in the NCAA’s Division I; its footballteams compete in the Football Bowl Subdivision (FBS; formerly Division I-A), the higher of two levels of NCAA Division I football competition. The conference’s 12 members, which are primarily flagship research universities in their respective regions, well-regarded academically, and with relatively large student enrollment, compete in 22 NCAA sports. It was created after the disbanding of the Pacific Coast Conference (PCC), whose principal members founded the Athletic Association of Western Universities (AAWU) in 1959, and went by the names Big Five, Big Six, Pacific-8, Pacific-10, and became the Pacific-12 in 2011.

Source: wikipedia