Home » Regions » North America » Eastern Temperate Forests » Mississippi Alluvial & Southeast USA Coastal Plains

Mississippi Alluvial & Southeast USA Coastal Plains

Page contents

To check where a specific point lies, you can look it up in our Ecoregion Locator.

Map Legend & Subregion List

This list will help you navigate the regions in case you have problems with viewing or clicking the interactive map above.

NameColor on MapCEC Code‡
Middle Atlantic Coastal Plain8.5.1
Mississippi Alluvial Plain8.5.2
Southern Coastal Plain8.5.3
Atlantic Coastal Pine Barrens8.5.4

† Status: ✓ = Complete ○ = Needs Image … = Incomplete ∅ = Stub Only

This code refers to the CEC's Level 3 ecoregion codes for North America, see here.


Partially Complete
With Images
Complete w/ Images

Get involved! You can help our ecoregion articles progress faster. Help us find photos of these regions. Contact us if you have any additions or corrections to any of these articles. You can also donate to support our ongoing work.

About the Mississippi Alluvial & Southeast USA Coastal Plains

The Mississippi Alluvial & Southeast USA Coastal Plains are a Level II ecoregion extending along the East Coast of the United States from Cape Cod, south through most of Florida, and along the Gulf Coast west to Mid-Louisiana, and extending northward in the Alluvial plain of the Mississippi river.

This region is mostly flatter, lower-lying (under 100m/320ft in elevation, with much of the coastal region being much lower), and warmer than the bordering Southeastern USA Plains. This area is mostly unglaciated except the terminal moraine and glacial outwashes that formed Long Island and Cape Cod. Most of the region is flat. There are extensive wetlands, river deltas, estuaries, and along the coast, barrier islands, beaches, and sand dunes. The soils have more sand, silt, and clay than in the more interior regions.

The climate is humid subtropical, milder than in the more interior regions. The northernmost limits of this region have four well-defined seasons, but the southernmost parts do not. Although there is some continental influence, the low altitude and proximity to the ocean moderates the climate and diminishes the influence of continental air masses. Precipitation averages similar amounts year-round, but arrives mostly from frontal systems in the cool season and more from convective thunderstorms, and hurricanes and other tropical storms in the warm season. Hurricanes are a major force in this area, especially in the southern coastal regions.

Land cover ranges from forest to wetlands to developed land. Wetlands and water are much more common over this region than inland. Pines are also more common here, dominating the forests in most coastal areas. Hardwood forests are more dominant in the more interior floodplains.

This area is heavily populated and also heavily utilized for agriculture and forestry. The biggest population centers in this region is Houston, TX, and other important ones are New Orleans, LA, Jacksonville, Tampa, and Orlando, FL, and the area around Virginia Beach.