The Marshall Islands is a nation of coral atolls in the North Pacific, in the Micronesia region of Oceania, roughly midway between Hawaii and Australia. It is known globally for two connected things: its role as the site of major United States nuclear weapons testing during the Cold War, and its status today as one of the world’s most climate vulnerable nations.

Where Is the Marshall Islands Located?

The Republic of the Marshall Islands lies in the North Pacific Ocean, in the Micronesia subregion of Oceania. It is made up of two parallel chains of atolls, the Ratak, meaning sunrise, and the Ralik, meaning sunset.

Geography of the Marshall Islands

The country comprises 29 atolls and 5 raised coral islands, of which 22 atolls and 4 raised islands are inhabited. Land is extremely low lying: individual islets are rarely more than 200 meters wide, and almost all land sits below 2 meters in elevation, a fact central to the country’s exposure to sea level rise. The capital, Majuro Atoll, held 23,156 residents at the time of the 2021 census, about 54 percent of the national population.

A Brief History of the Marshall Islands

The islands were settled by Micronesian voyagers in ancient times. Germany established a protectorate in 1885, and Japan seized the islands during the First World War, administering them from 1914 to 1945 as a League of Nations mandate. After the Second World War, the Marshall Islands became part of the Trust Territory of the Pacific Islands, a United Nations trusteeship administered by the United States.

Between 1946 and 1958, the United States conducted 67 nuclear weapons tests across the northern Marshall Islands, including 16 at Bikini Atoll alone, all atmospheric or surface detonations. Affected populations were relocated, and radioactive contamination required extensive later remediation, including a 1995 review convened by the International Atomic Energy Agency at the Marshallese government’s request. The Marshall Islands adopted its constitution in 1979, and the Compact of Free Association with the United States entered into force on October 21, 1986, the date treated as the country’s effective independence; it joined the United Nations in 1991. Under the Compact, the United States provides economic assistance and defense responsibility in exchange for exclusive military access to Marshallese land and waters, an arrangement renewed in 2024.

Government and Economy

The Marshall Islands has a constitutional government in free association with the United States, with a parliamentary system and a unicameral legislature, the Nitijela.

According to the World Bank, GDP reached approximately 308 million dollars in 2025, with GDP per capita around 8,489 dollars and growth of about 2.3 percent. Remittances account for roughly 23.5 percent of GDP, reflecting significant emigration, much of it to the United States under the Compact’s free movement provisions; the population has been declining at an annual rate of around 2 to 3 percent in recent years. The country hosts the US Army’s Kwajalein Atoll missile defense testing installation, a major strategic and economic factor in its relationship with the United States.

Culture and People

Marshallese and English are both official languages, and the US dollar is the currency in use. The 2021 census recorded 42,418 residents, with about 78 percent living in the urban centers of Majuro and Ebeye.

What Is the Marshall Islands Known For?

The Marshall Islands is globally known above all for Bikini Atoll, the site of the 1946 to 1958 nuclear tests, including the 1954 Castle Bravo detonation, the largest nuclear weapon the United States ever tested. UNESCO inscribed Bikini Atoll as a World Heritage Site specifically as an outstanding example of a nuclear test site, recognizing both its role in launching the nuclear age and the global disarmament movements it later helped inspire. The country’s second defining global association is its extreme exposure to climate change, since nearly all of its land lies less than 2 meters above sea level.

Why the Marshall Islands Matters

The Marshall Islands matters as a living reminder of the human and environmental costs of Cold War nuclear testing, and as one of the clearest real world examples of a nation facing existential risk from sea level rise. Both legacies continue to shape its relationship with the United States and its advocacy in international climate and disarmament forums today.

Key Takeaways

• The Marshall Islands comprises 29 atolls and 5 raised coral islands in the North Pacific, with almost all land below 2 meters in elevation.
• The United States conducted 67 nuclear tests in the northern Marshall Islands between 1946 and 1958, including 16 at Bikini Atoll.
• Bikini Atoll is a UNESCO World Heritage Site, recognized as an outstanding example of a nuclear test site.
• The Compact of Free Association with the United States took effect in 1986, providing economic assistance and defense in exchange for military access.
• Remittances make up about 23.5 percent of GDP, reflecting substantial emigration under the Compact’s free movement provisions.

Sources

• US Mission to the UN (RMI), “Country Facts,” https://www.un.int/marshallislands/marshallislands/country-facts
• World Bank Climate Change Knowledge Portal, “Marshall Islands Climate Risk Country Profile,” https://climateknowledgeportal.worldbank.org/sites/default/files/country-profiles/15817-WB_Marshall%20Islands%20Country%20Profile-WEB.pdf
• IAEA Bulletin 40/4/1998, “Radiological Conditions at Bikini Atoll,” https://www.iaea.org/sites/default/files/publications/magazines/bulletin/bull40-4/40405081517.pdf
• US Department of the Interior, Office of Insular Affairs, “The Marshall Islands,” https://www.doi.gov/oia/islands/marshallislands
• UNESCO World Heritage Centre, “Bikini Atoll Nuclear Test Site,” https://whc.unesco.org/en/list/1339
• World Bank, Marshall Islands data, https://data.worldbank.org/country/marshall-islands
• Republic of the Marshall Islands, “2021 Census Report, Volume 1,” https://rmihealth.org/media/attachments/2025/08/08/marshall_islands_2021_census_vol1_table_report.pdf

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed September 28, 2026Researched and drafted with AI assistanceReport an issue