In North American sports, realignment or releaguing refers to a major change in the competitive structure of one or more existing leagues.
Divisions are usually based on geography, both to minimise travel costs and to encourage regional rivalries.
For instance, when the Atlanta Thrashers of the NHL became the Winnipeg Jets in 2011, they would have been a team from a northwestern city playing in the Southeast Division, but the NHL chose not to realign at this time, leading to lengthy road trips for the Jets and the other teams in their division.
The National Football League realigned to its current eight-division format after a series of team relocations had created geographically skewed divisions.
In college sports, the term "realignment" is used to refer to a situation in which large numbers of schools switch their conference affiliation in a short period of time.