The lowest, flattest part of the Atlantic Coastal Plain is called the Coastal Lowlands.

This region is characterized by:

* Low elevation: It's generally less than 200 feet above sea level.

* Flat topography: It has a very gentle slope, resulting in a wide, flat landscape.

* Abundant wetlands: The low elevation and proximity to the coast lead to the presence of swamps, marshes, and other wetlands.

* Presence of barrier islands: These islands help protect the mainland from storm surges and erosion.

The Coastal Lowlands are a significant part of the Atlantic Coastal Plain, stretching from the Gulf of Mexico to the Canadian Maritimes.