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 subsidence in the central region, as well as heavy sedimentation around the Florida Platform and Northern Gulf of Mexico. While a few intrusive igneous formations found as far south as Mexico City are dated to the Late-Jurassic or Early Cretaceous, the Gulf of Mexico during that time was relatively devoid of igneous activity. It wasn't until the Late Mesozoic that low-volume yet widespread volcanism occurred along the Western and Northwestern margins of the Gulf of Mexico, leaving the Yucatan Peninsula with an extremely alkali volcanic field in the subsurface. The volcanism is believed to have been activated along ancient plate