Atlantic Plain
The Atlantic Plain is one of eight different United States physiographic (Physical part of) regions. The Atlantic Coast of the United States comprises the coastal states of Delaware, Florida, Maine, North Carolina, Maryland, New Jersey, New York, South Carolina, Virginia, and Puerto Rico. The land next to the Atlantic coast are made up of sandy beaches, marshlands, bays, and barrier islands. This big part is made up of the Continental Shelf and Coastal Plain provinces. It is the flattest of the U.S. physiographic divisions and is over 2,200 miles (3,500 km) in length from Cape Cod to the Mexican border and goes south an additional 1,000 miles (1,600 km) to the Yucatán Peninsula. The central and southern Atlantic Coast is seen by barrier and drowned valley coasts. The coastal Atlantic plain features long barriers interrupted by inlets, large embayments with drowned river valleys, and extensive wetlands and marshes. The Atlantic plain slowly lowers to sea level from the inland highlands in a series of terraces. This continues far into the Atlantic and Gulf of Mexico, forming the continental shelf. The difference at the land-sea interface is so hard to see that the boundary between them is often indistinct(hard to see), especially along stretches of the Louisiana bayous and the Florida Everglades.