It is composed of the following parishes (counties): Allen, Beauregard, Calcasieu, Cameron, and Jefferson Davis.

[3] Southwest Louisiana has one metropolitan area: Lake Charles.

The southwestern portion of Louisiana is also geographically and culturally attached to Southeast Texas.

Three of the parishes — Calcasieu, Cameron, and Jefferson Davis — are also part of Acadiana, the region of French and Acadian influence defined by the Louisiana State Legislature in 1971.

[4] "Southwest Louisiana" is often used to represent a broader region that includes parishes farther east.