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 Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

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.

Locations

Some of the largest coastal plains are in

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

and the southeastern

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. The

Gulf Coastal Plain The Gulf Coastal Plain extends around the Gulf of Mexico in the Southern United States and eastern Mexico. This coastal plain reaches from the Florida Panhandle, southwest Georgia (U.S. state), Georgia, the southern two-thirds of Alabama, over m ...

of North America extends northwards from the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

along the Lower Mississippi River to the

Ohio River The Ohio River () is a river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing in a southwesterly direction from Pittsburgh, Pennsylvania, to its river mouth, mouth on the Mississippi Riv ...

, which is a distance of about . The

Atlantic Coastal Plain The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

runs from the New York Bight to Florida. The Coastal Plains of India lie on either side of the

Deccan Plateau The Deccan is a plateau extending over an area of and occupies the majority of the Indian peninsula. It stretches from the Satpura Range, Satpura and Vindhya Ranges in the north to the northern fringes of Tamil Nadu in the south. It is bound ...

, along the western and eastern coasts of India. They extend for about 6,150 km from the Rann of Kutch in the west to West Bengal in the east. They are broadly divided into the Western Coastal Plains and the Eastern Coastal Plains. The two coastal plains meet at Kanyakumari, the southernmost tip of the Indian mainland. The eastern coastal plain is located between The Bay of Bengal and the eastern Ghats and the western coastal plain is located between the

Arabian Sea The Arabian Sea () is a region of sea in the northern Indian Ocean, bounded on the west by the Arabian Peninsula, Gulf of Aden and Guardafui Channel, on the northwest by Gulf of Oman and Iran, on the north by Pakistan, on the east by India, and ...

and the western Ghats. In Australia, there exists the South East Coastal Plain in Victoria that includes the Gippsland Plain, the eastern portion of

Melbourne Melbourne ( , ; Boonwurrung language, Boonwurrung/ or ) is the List of Australian capital cities, capital and List of cities in Australia by population, most populous city of the States and territories of Australia, Australian state of Victori ...

, Otway Plain and Warrnambool Plain subregions. The Gippsland Plain features the depressed coastal and alluvial plains, barrier dunes and swampy flatlands. They mostly consist of grassland and grassy woodlands on yellow and grey textured fertile soils.South East Coastal Plain
Biodiversity of South-Eastern Australia. Retrieved December 11, 2024. Another is the Swan Coastal Plain in

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

, which includes the city of

Perth Perth () is the list of Australian capital cities, capital city of Western Australia. It is the list of cities in Australia by population, fourth-most-populous city in Australia, with a population of over 2.3 million within Greater Perth . The ...

.IBRA Version 6.1
data It is one of the distinct physiographic provinces of the larger West Australian Shield division.

References

{{topography-stub Coastal and oceanic landforms Coastal plains

Formation

Locations

See also

References