A coastal plain is an area of flat, low-lying land adjacent to a seacoast and separated from the interior by other features. One of the world's longest coastal plains is located in western South America. The southeastern coastal plain of North America is notable for its species diversity. The Gulf Coastal Plain of North America extends northwards from the Gulf of Mexico along the Lower Mississippi River to the Ohio River, which is a distance of about 500 miles (about 800 km). During the Cretaceous age, the central area of the United States was covered by a shallow sea, which disappeared as the land rose. Large fossilized aquatic birds called Hesperornis and Ichthyornis, found in western Kansas, indicate that the shallow sea was rife with fish. The coastal plain lying alongside the lower Mississippi River may be associated with a shallow sea which had existed 100 million years ago.

Some well-known coastal plains

• The Illawarra Plains, New South Wales, Australia
• The Swan Coastal Plain, Western Australia
• The Israeli Coastal Plain
• The Atlantic Coastal Plain, United States
• The Oxnard Plain, California, United States, near Los Angeles
• The Prehistoric Shoreline, Georgia, United States

See also

• Coastal prairie
• Field
• Flooded grasslands and savannas
• Flood-meadow
• Grassland
• Meadow
• Pasture
• Plain
• Prairie
• Rangeland
• Savanna
• Steppe
• Water-meadow
• Wet meadow
• Veld