The Diego Garcia atoll, a remote landform in the central Indian Ocean, holds a unique and complex status shaped by its geography and its geopolitical history. Located just south of the equator, this isolated territory has become a focal point of international interest due to colonial power, military strategy, and a long-standing human rights dispute. The atoll’s history is a microcosm of 20th-century geopolitical maneuvering, where the strategic value of a location superseded the rights of its resident population. Its future remains tied to ongoing legal and diplomatic negotiations that seek to reconcile historical injustice with modern security concerns.
Geography and Physical Description
Diego Garcia is the largest and southernmost atoll in the Chagos Archipelago, a collection of 55 islands that form part of the British Indian Ocean Territory (BIOT). An atoll is a ring-shaped coral reef that partially or completely encircles a central lagoon. The atoll’s landmass forms a distinct, V-shaped rim, approximately 40 miles (64 km) long, enclosing a vast, deep-water lagoon.
The total land area is small, covering about 17 square miles (44 square km), with a maximum elevation rarely exceeding 22 feet (7 meters) above sea level. This low elevation makes it highly vulnerable to rising sea levels. Situated approximately 1,116 miles (1,796 km) southwest of India and 1,800 nautical miles (3,334 km) east of the African coast, its extreme isolation and central position underpin its immense strategic value.
The Displacement of the Chagossian People
The history of the atoll is inseparable from the people who lived there, known as the Chagossians or Ilois, whose community was forcibly removed to facilitate military development. The population were descendants of enslaved people brought from Africa and Madagascar, and indentured laborers from India, who had built a distinct Creole culture working on copra and coconut oil plantations since the late 18th century. In 1965, the United Kingdom created the British Indian Ocean Territory (BIOT) by separating the Chagos Archipelago from the colony of Mauritius, explicitly preparing for a joint defense facility.
The UK government simultaneously agreed with the United States to make Diego Garcia available for military purposes, contingent on the island being unpopulated by a civilian community. Between 1968 and 1973, the entire Chagossian population was systematically removed from Diego Garcia and the other inhabited atolls. The removal involved coercive tactics, including restricting supplies and ordering the killing of their pets, before deporting them to Mauritius and the Seychelles, where they were often left in poverty.
This forced displacement led to decades of legal and political struggle by the Chagossians for the right to return to their homeland. Although the UK High Court found the expulsion unlawful in 2000, subsequent legal decisions upheld the government’s right to prevent their return. This injustice remains a central focus of the ongoing sovereignty dispute.
Strategic Role of the Military Base
Today, Diego Garcia functions as the Naval Support Facility Diego Garcia, a joint US/UK military installation known as a “forward operating location.” The base’s primary mission is to provide logistical and operational support for US and allied forces across the Indian Ocean, Arabian Gulf, and broader Indo-Pacific region. Its location is strategically significant, allowing for the projection of air and naval power across a vast area encompassing the Middle East, Africa, and Asia.
The base features a deep-water port capable of accommodating large naval vessels and an extensive 12,000-foot (3,659-meter) runway that can handle heavy bombers and large military transport aircraft. The installation serves as a logistics hub, housing a Maritime Prepositioning Ship Squadron with equipment and supplies to support an entire Army or Marine Corps brigade in a rapid-deployment scenario. This capability has been leveraged for operations in the Middle East and Afghanistan.
The military presence is governed by a long-term agreement between the UK and the US, initially signed in 1966 for 50 years, which was automatically extended until 2036. The agreement requires the UK to maintain the island as an area without a permanent civilian population. The base is currently staffed by US and UK military personnel and contractors.
The Ongoing Sovereignty Dispute
The legal status of the Chagos Archipelago, including Diego Garcia, has been contested by Mauritius since its independence in 1968. Mauritius maintains the archipelago was unlawfully detached from its territory, arguing that the separation violated international law and resolutions against the breakup of colonies prior to independence. The dispute escalated when the United Nations General Assembly sought an advisory opinion from the International Court of Justice (ICJ).
In a 2019 advisory opinion, the ICJ ruled that the UK’s separation of the Chagos Archipelago from Mauritius in 1965 was unlawful and that the decolonization process was not legitimately completed. The court concluded that the UK is obligated to end its administration of the archipelago “as rapidly as possible.” Following this, the UN General Assembly voted to support the ICJ’s opinion and demanded that the UK withdraw from the territory.
Diplomatic pressure led to bilateral negotiations, resulting in the UK and Mauritius signing an agreement to transfer sovereignty of the Chagos Archipelago. This deal ensures the continued operation of the US/UK military base on Diego Garcia, involving the UK leasing the base from Mauritius for an initial period of 99 years. This aims to resolve the sovereignty issue while securing the long-term strategic interests of the US and UK in the Indian Ocean.