Mississippi Gulf Coast Mississippi Gulf Coast The Mississippi Gulf Coast, also known as the Mississippi Gulf Coast region, or simply The Coast, is the area of southern Mississippi along the Mississippi Sound along the Gulf Of Mexico. The term has traditionally referred to the three counties that lie directly on the Mississippi Sound that meet up with the Gulf of Mexico within the state: Hancock County, Harrison County, and Jackson County. The U. S. Census Bureau divided the Metropolitan Statistical Area (MSA) for the Mississippi Gulf Coast in 2003, which previously had been the three coastal counties, into two MSAs that included two
Gulf of Mexico basin 20 kilometers. Beneath the sediments of the Gulf of Mexico basin, most of the pre-Triassic basement rocks are believed to be allochthonous thrust sheets sutured during the formation of Pangaea. However, it was during the break-up of the supercontinent that the foundation for the Gulf of Mexico sediments would be lain. Prior to the rifting which formed the Gulf of Mexico basin, extensional deformation in the Late-Triassic caused by the breakup up of Pangaea, and more specifically the rifting of the Atlantic Ocean, created basement graben formations which filled with terrestrial red bed sediments, and volcanic sediments from the eruption