The Southeastern Plains, a large ecoregion in the eastern US, is a region in the United States consisting of the Eastern Temperate Forests. This ecoregion is located east of the Mississippi, extending north through this river valley to Tennessee and following a U-shape on the map, first south into the southern states (MS, AL, GA) and then northeast along the east coast to Virginia and Maryland, but give way any further northward to the Mid-Atlantic Coastal plains and the Atlantic Coastal Pine Barrens ecoregions.

The southeast plains along the east coast are found between the Appalachian Mountains to the west and the wide Coastal Plains to the east. However, the southeast plains along the Gulf coast are much wider and larger area of land with only a small swatch of coastal plains from the Gulf waters.

Historically, much of this land was covered with hardwood forests, with occasional mixed and coniferous forests in some areas. In much of the southern reaches of this ecoregion, pine forest are more common. Also found in interior areas, but not necessarily dominant, are broadleaf evergreen shrubs and trees.

Wetland of substantial size are found but no were near as massive as those found in the alluvial plains and coastal plain ecoregions. The land use currently in practice have developed this ecoregion into a patchwork of agricultural lands, forest, and urban development.

Topography of this ecoregion is primarily flat with some rolling hills and except for the north easternmost area, the ecoregion is unglaciated.

Climate is humid subtropical with the northeastern area near the colder edges of the subtropical. The four seasons are well defined in the north but blur as one moves further south. In areas without predominate mountain ranges, temperatures and humidity have more of continental effect, which can cause large swings in the weather caused from continental jet streams interacting with the warm air from the Gulf of Mexico. This region experiences moderate levels of rainfall.

In some places, this ecoregion is heavily populated, especially in areas in and around the metropolitan areas of Washington, D.C., Annapolis, MD, Baltimore, MD, Richmond, VA, Colunmbia, SC, Tallahassee, FL and Montgomery, AL.

This ecoregion is being used throughout for agriculture, pasture lands, and in the southern area, is heavily used for forestry. There is serious treats of habitat loss and a high importation of invasive plants.

Jamestown Colony