thumb|right|Florida's [[Everglades is a popular outdoor site on the Atlantic coastal plain.]]
A coastal plain (also coastal plains, coastal lowland, coastal lowlands) is an area of flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and an upland area.
Formation
Coastal plains can form in one of two ways; some begin as a continental shelf, a flat piece of land located below sea level, and are created when the ocean level falls, exposing the land. Others develop when river currents carry sediment into the ocean, which is deposited and builds up over time until it forms a coastal plain. They are generally separated from the rest of the interior by proximate landforms, like mountains. Another is the Swan Coastal Plain in Western Australia, which includes the city of Perth. It is one of the distinct physiographic provinces of the larger West Australian Shield division.
See also
- Alluvial plain
- Atlantic Plain
- Coastal plains of Chile
- Israeli coastal plain
- Mississippi embayment
- North European Plain