Geography of the Marshall Islands: Location, Topography, Geology | Sea Life, Islands and Oceania

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GEOGRAPHY OF THE MARSHALL ISLANDS

Marshall Islands

The Marshall Islands consists of 29 atolls and five isolated islands in the North Pacific Ocean, about halfway between Hawaii and Australia. The atolls and islands are situated in two north-south-running, almost-parallel island chains: the Ratak (Sunrise) group and the Ralik (Sunset) group. The are 1,225 islands and islets and 22 of the atolls and four of the islands are uninhabited. Many go unvisited for months or even years at a time.[Source: CIA World Factbook]

The Marshall Islands takes its name from one of the country's islands, named after British Captain William Marshall, who explored the area with Captain Thomas Gilbert in 1788, and are located in the Pacific Ocean, just north of the equator, between 4° and 15° north , about 3,220 kilometers (2,000 miles) east of Guam, 3,438 kilometers (2,136 miles) west of Honolulu and 3,701 kilometers (2,300 miles) southeast of Tokyo.

The Marshall Islands are scattered across roughly 1.94 million square kilometers (750,000 square miles) of open Pacific Ocean. However, the total land area of the 1,225 islands is only about 181 square kilometers (70 square miles), approximately the size of Washington, D.C. Most of the islands are part of the two parallel chains of atolls that are about 210 kilometers (130 miles) apart and extend from the northwest to the southeast for about 1,290 kilometers (800 miles). The Ratak (eastern, or sunrise) chain is made up of 15 atolls, while the Ralik (western, or sunset) chain consists of 16 atolls. The islands closer to the equator generally have more vegetation than those farther north.

The islands of the Marshall Islands are low coral limestone and sand islands. The islands of Bikini and Enewetak are former US nuclear test sites. The island city of Ebeye is the second largest settlement in the Marshall Islands, after the capital of Majuro, and one of the most densely populated locations in the Pacific. Other major atolls are Arno; Ailinglaplap and Jaluit. The latter has a fine natural harbor, and serves as the archipelago's chief trade center.

Administrative Divisions: 24 municipalities; Ailinglaplap, Ailuk, Arno, Aur, Bikini & Kili, Ebon, Enewetak & Ujelang, Jabat, Jaluit, Kwajalein, Lae, Lib, Likiep, Majuro, Maloelap, Mejit, Mili, Namorik, Namu, Rongelap, Ujae, Utrik, Wotho, Wotje. [Source: CIA World Factbook]

Geographical Data for the Marshall Islands

The Marshall Islands is the 7th smallest country in the world by land area. Area: total: 181 square kilometers (70 square miles); land: 181 square kilometers (70 square miles); water: 0 square kilometers (0 square miles). Note: the archipelago includes 11,673 square kilometers (4,507 square miles) of lagoon waters and encompasses the atolls of Bikini, Enewetak, Kwajalein, Majuro, Rongelap, and Utirik. Elevation: highest point: East-central Airik Island, Maloelap Atoll 14 meters (46 feet); lowest point: Pacific Ocean 0 meters; mean elevation: 2 meters (7 feet). Geographic Coordinates: 9 00 N, 168 00 E, between 160° and 173° east and 4° and 20° N. Majuro lies west of the international date line, putting it 17 hours ahead of Eastern Standard (New York) Time.

Locations of the Marshall Islands

Coastline: 370.4 kilometers (230.2 miles); Maritime claims: territorial sea: 12 nautical miles; contiguous zone: 24 nautical miles; exclusive economic zone: 200 nautical miles. Land Boundaries: total: 0 kilometers (0 miles);

Land Use: agricultural land: 50.7 percent (2018 estimate). Arable Land: 7.8 percent (2018 estimate); permanent crops: 31.2 percent (2018 estimate); permanent pasture: 11.7 percent (2018 estimate); forest: 49.3 percent (2018 estimate); other: 0 percent (2018 estimate). Irrigated Land: 0 square kilometers (0 square miles) (2022). Arable land is land cultivated for crops like wheat, maize, and rice that are replanted after each harvest. Permanent crops is land cultivated for crops like fruit trees oranges that are not replanted after each harvest

Population Distribution: The population is distributed throughout the 22 inhabited atolls, living in urban clusters found on many of the country's islands. More than two-thirds of the population lives on the atolls of Majuro and Ebeye. The outer islands are sparsely populated due to lack of employment opportunities and economic development. Kwajalein is the site of a U.S. missile-testing base. Bikini and Enewetak are uninhabited because of nuclear contamination from atomic and hydrogen bomb testing between 1946 and 1958.

Islands and Atolls

Ocean islands are basically divided into three types: 1) "low" coral and sand islands; 2) "high" islands (usually exposed peaks and ridge-tops of submerged mountains and volcanoes); and 3) parts of the continental shelf. Some continental islands were mountains and hills along the coast during the last Ice Age when ocean levels were lower.

Low islands or cays were formed on coral shoals from reef sediments. Atoll islands are low islands (See Below). Seabird droppings fertilize the soils of some of these islands, which allow scrubby forest to take root. Others are battered regularly by storms and are little more than shifting piles of sand. Some patches of sand are so low they disappear during low tide and lose their status as islands.

Majuro and Arno Atolls

High islands generally have better soil and a better supply of water than low islands. Low islands support only a few species of plants because there is little topsoil and this soil has a high salt content. Although they often have no visible water sources they are often positioned over water lenses that trap rainwater and can provide fresh water through wells.

An atoll is a group of islands that encircle a central lagoon. Classic atolls develop on the top guyots, flat-topped volcanic sea mounts, that rise above the sea and then erode and sink under the weight of the coral reefs that grow on their slopes. A classic atolls begins as a reef that forms around a high island. As the island sinks under the weight of the coral reef, the coral reef grows upwards causing the island to sink even more. This process eventually forms a barrier reef which is separated from the shore by a shallow lagoon. Eventually the original mountain becomes completely submerged and islands are created from the coral and sand deposits that accumulate on the highest points of the reef. These islands often roughly follow the contour of the original mountain top. The atoll-making process takes hundreds of thousands or millions of years.

Marshall Islands Atolls

The Marshall Islands contain about 10 percent of the world's atolls, including the largest, second-largest, and fourth-largest atolls in the world. The atolls that make up the Marshall Islands developed on flat-topped volcanic seamounts that once rose above the sea and later sank under the weight of the coral reefs that grew around the fringes of the mountains. Classic atoll islands are narrow and flat and are grouped around a central lagoon. Entiwetok Atoll is a circle of calcium carbonate rock 34 kilometers (21 miles) wide, 42 kilometers (26 miles) long and 1,524 meters (5,000 feet) thick.

Atoll islands are usually low, long and narrow and circle a lagoon between many or several islands. The lagoons of some atolls are so large that it is difficult to see all the islands from any particular point. All of the Marshall Islands atolls have islands with white-sand beaches. Some islands are so low that they disappear during high tide, while others become connected during low tide. The widest island, Wotje, is less than 1 mile (1.6 kilometers) wide. The highest elevation, 34 feet (10.4 meters), is found on Likiep. There are more than 800 major reefs in the Marshall Islands.

The Ratak (Sunrise) Group contains Mili, Majuro, Maloelap, Wotje, Likiep, Rongelap, Ailinginae, Bikini, Enewetok, and Ujelang Atolls. The Sunset (Ralik) Group includes Namorik, Ebon, Jaluit, Ailinglaplap, and Kwajalein Atolls. Calalien Pass, the main channel in Majuro, is deep and wide; its configuration allows large container ships to pass between the ocean and the lagoon. The ocean floor around the Marshall Islands is also the final resting several Japanese and American warship sunk during World War II (1941-45). [Source: Junior Worldmark Encyclopedia of Physical Geography, 2003]

Characteristics of Marshall Islands Atolls

Satellite image of Marshall Islands in March 1999

The Marshall Islands have very little topsoil and no rivers. Fresh water is scarce. Most of the islands can be walked across in a few minutes, and about the only things that will grow on them are coconut trees, pandanus and breadfruit. Most of the Marshall Islands support only a few species of plants because there is little topsoil, and the soil that does exist has a high salt content.

There are no lakes. The Marshall Islands are too small to support any bodies of water larger than small ponds. Most of the flat areas have sandy soils. The islands in the south receive more rainfall and therefore support more vegetation than the islands in the north. Although marine resources are abundant, poor soil provides few opportunities for agriculture. The only revenue sources for for outer islanders are fishing and the harvesting and drying of coconut meat into copra. About 8,900 hectares (22,000 acres) of land is planted with coconut palms. [Source: Junior Worldmark Encyclopedia of Physical Geography, 2003]

Most atolls have free-flowing ocean water across the reef with one or two openings for boats to enter the lagoon. The islands of most atolls are not contiguous, with open reef stretches extending for miles between islands. Since the distances between islands in an atoll can be many kilometers (miles), traveling from island to island within an atoll can be difficult even with a boat. The longest paved road in The Marshall Islands runs through the islands on the southern side of Majuro Atoll, which have been artificially joined by a 53-kilometer (32-mile) continuous road over the years. [Source: Encyclopedia.com, adapted from the Department of State Post Report 2001]

Micronesia Region

The Federated States of Micronesia (FSM) is the name of a new country created in 1979 from former Japanese Pacific territories taken over by the U.S. after World War II. It includes the island states of Yap, Chuuk, Pohnpei, Kosrae, and numerous atolls in the area of these island states. The term Micronesia is also used to describe the islands in a region that stretch from Hawaii to the Philippines and includes FSM as well as Guam, the Commonwealth of the Northern Marianas, the Republic of Palau and the Republic of the Marshall Islands.

The region known as Micronesia ("small islands") is divided geographically into three archipelagoes: the Marshall Islands, the Marianas (including Guam and Saipan) and the Caroline Islands. The four states of the Federated States of Micronesia—Kosrae, Pohnpei, Chuuk and Yap— are all part of the Caroline Islands, which in turn are divided into the Western Caroline Islands (Palau, Yap and Chuck) and the Eastern Caroline Islands (Pohnpei and Kosrae).

States in the Micronesia Region
Federated States of Micronesia (FSM): 702 square kilometers (271 square miles).
Guam: 549 square kilometers (212 square miles), the largest single island in Micronesia.
Commonwealth of the Northern Mariana Islands: 463 square kilometers (179 square miles) distributed across 15 islands.
Republic of Palau: 466–489 square kilometers (180–189 square miles) spread over approximately 340 islands.
Republic of the Marshall Islands: 181 square kilometers (70 square miles)

Each group of islands has a "district center," with an international airport, and the majority of the government offices, medical facilities and tourist facilities. The main district centers are Majuro (Marshall Islands), Koror (Palau), Saipan (Northern Marianas), Pohnpei, Weno Island (Chuuk), Yap Proper (Yap) and Kosrae.

Image Sources: Wikimedia Commons

Text Sources: CIA World Factbook; “Encyclopedia of World Cultures, Volume 2: Oceania,” edited by Terence E. Hays, 1991, Wikipedia, New York Times, Washington Post, Los Angeles Times, Encyclopedia.com, Lonely Planet Guides, Library of Congress, The Guardian, National Geographic, Smithsonian magazine, The New Yorker, Reuters, Associated Press, AFP, BBC, CNN, and various books, websites and other publications.

Last updated July 2026