Coastal Plains

Coastal Plains. Photo credit: National Park Service. Click the image to open the Coastal Plains gallery.

The West Gulf Coastal Plain encompasses the easternmost portion of Texas along the Gulf of Mexico, and the state of Louisiana. The West Gulf Coastal Plain is the westernmost part of the larger Gulf-Atlantic Coastal Plain, which includes eastern Texas, Louisiana, Mississippi, Alabama and Florida, and portions of the eastern states along the Atlantic Ocean.

Area: The West Gulf Coastal Plain covers roughly 45,250 sq km (17,470 sq miles) in northeastern Texas and Louisiana, and an additional 276,460 sq km (106,740 sq miles) along the full eastern side of Texas along the Gulf of Mexico.

Precipitation: Precipitation in the West Gulf Coastal Plain averages between 102 cm (40 in) and 135 cm (54 in) annually. Humidity remains high throughout the year, with increasing precipitation from north to south.

Temperature: Summer temperatures above 90 degrees F are common, and even in January the average high is around 50 degrees F. Annual temperatures typically increases from north to south, and most Coastal Plains locations see few to no days below freezing throughout the year.

Elevation: Overall, the Coastal Plains are low elevation, ranging between sea level and approximately 60 m (200 ft). The West Gulf Coastal Plain, however, displays more topographical variation, ranging from 25 m to 200 m (80 to 660 ft) away from the ocean shores.

Life Zones: Louisianan

Vegetation: The Coastal Plains support a variety of vegetative environments, including upland prairies and savannas, bottomland forests (oak, pine, and hickory), saturated grasslands, dunes, marshes, estuaries, and tidal flats. Historically, long-leaf pine forests dominated the northern reaches of the West Gulf Coastal Plain.

Geology: The West Gulf Coastal Plain is a relatively level, drained alluvial plain overlain in some places with sandy dunes, and underlain by sedimentary rocks. Soils are mostly clays and clay loams in addition to sands and sandy loams.

Prehistoric Cultures: Plains Woodland Tradition.

National Parks: None in the greater Southwest region.