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 boundaries weakened by the loading of sediments in the Gulf. As mentioned above, the pre-rift stratigraphy of the central Gulf of Mexico basin, which now lies beneath nearly 20 kilometers of sediment deposited during the Jurassic through the Holocene, is made up primarily of extensional graben formations filled with "red beds," basalt flows, and diabase dikes and sills deposited and intruded during the break-up of Pangaea and the explosion of the Central Atlantic Magmatic Plume. Red beds, also referred to as non-marine clastic sequences, which are often red in color, have been found in wells drilled in the Gulf of