Introduction
Background
Formerly administered as part of the British Crown Colony of Mauritius, the British Indian Ocean Territory (BIOT) was established as an overseas territory of the UK in 1965. A number of the islands of the territory were later transferred to the Seychelles when it attained independence in 1976. Subsequently, BIOT has consisted only of the six main island groups comprising the Chagos Archipelago. Only Diego Garcia, the largest and most southerly of the islands, is inhabited. It contains a joint UK-US naval support facility and hosts one of four dedicated ground antennas that assist in the operation of the Global Positioning System (GPS) navigation system (the others are on Kwajalein (Marshall Islands), at Cape Canaveral, Florida (US), and on Ascension Island (Saint Helena, Ascension, and Tristan da Cunha)). The US Air Force also operates a telescope array on Diego Garcia as part of the Ground-Based Electro-Optical Deep Space Surveillance System (GEODSS) for tracking orbital debris, which can be a hazard to spacecraft and astronauts.
Between 1967 and 1973, former agricultural workers, earlier residents in the islands, were relocated primarily to Mauritius, but also to the Seychelles. Negotiations between 1971 and 1982 resulted in the establishment of a trust fund by the British Government as compensation for the displaced islanders, known as Chagossians. Beginning in 1998, the islanders pursued a series of lawsuits against the British Government seeking further compensation and the right to return to the territory. In 2006 and 2007, British court rulings invalidated the immigration policies contained in the 2004 BIOT Constitution Order that had excluded the islanders from the archipelago, but upheld the special military status of Diego Garcia. In 2008, the House of Lords, as the final court of appeal in the UK, ruled in favor of the British Government by overturning the lower court rulings and finding no right of return for the Chagossians. In March 2015, the Permanent Court of Arbitration unanimously held that the marine protected area that the UK declared around the Chagos Archipelago in April 2010 was in violation of the UN Convention on the Law of the Sea.
In February 2019, the International Court of Justice ruled in an advisory opinion that Britain’s decolonization of Mauritius was not completed lawfully because of continued Chagossian claims. A non-binding May 2019 UN General Assembly vote demanded that Britain end its “colonial administration” of the Chagos Archipelago and that it be returned to Mauritius. UK officials defend Britain's sovereignty over the islands and argue that the issue is a bilateral dispute between Mauritius and the UK that does not warrant international intervention.
Visit the Definitions and Notes page to view a description of each topic.
Geography
Location
archipelago in the Indian Ocean, south of India, about halfway between Africa and Indonesia
Geographic coordinates
6 00 S, 71 30 E;note - Diego Garcia 7 20 S, 72 25 E
Map references
Political Map of the World
Area
total: 60 sq km
land: 60 sq km (44 Diego Garcia)
water: 54,340 sq km
note: includes the entire Chagos Archipelago of 55 islands
comparison ranking: total 229
Area - comparative
land area is about one-third the size of Washington, DC
Land boundaries
total: 0 km
Coastline
698 km
Maritime claims
territorial sea: 12 nm
Environment (Protection and Preservation) Zone: 200 nm
Climate
tropical marine; hot, humid, moderated by trade winds
Terrain
flat and low coral atolls (most areas do not exceed two m in elevation); sits atop the submarine volcanic Chagos-Laccadive Ridge
Elevation
highest point: ocean-side dunes on Diego Garcia 9 m
lowest point: Indian Ocean 0 m
Natural resources
coconuts, fish, sugarcane
Land use
agricultural land: 0% (2018 est.)
arable land: 0% (2018 est.)
permanent crops: 0% (2018 est.)
permanent pasture: 0% (2018 est.)
forest: 0% (2018 est.)
other: 100% (2018 est.)
Natural hazards
none; located outside routes of Indian Ocean cyclones
Geography - note
note 1: archipelago of 55 islands; Diego Garcia, the largest and southernmost island, occupies a strategic location in the central Indian Ocean; the island is the site of a joint US-UK military facility
note 2: Diego Garcia is the only inhabited island of the BIOT and one of only two British territories where traffic drives on the right, the other being Gibraltar
People and Society
Population
no indigenous inhabitants
note: approximately 1,200 former agricultural workers resident in the Chagos Archipelago, often referred to as Chagossians or Ilois, were relocated to Mauritius and the Seychelles in the 1960s and 1970s; approximately 3,000 UK and US military personnel and civilian contractors living on the island of Diego Garcia (2018)
Age structure
0-14 years: NA
15-64 years: NA
65 years and over: NA
Dependency ratios
total dependency ratio: NA
youth dependency ratio: NA
elderly dependency ratio: NA
potential support ratio: NA
Drinking water source
improved: urban: NA
rural: NA
total: NA
unimproved: urban: NA
rural: NA
total: NA
Environment
Environment - current issues
wastewater discharge into the lagoon on Diego Garcia
Climate
tropical marine; hot, humid, moderated by trade winds
Land use
agricultural land: 0% (2018 est.)
arable land: 0% (2018 est.)
permanent crops: 0% (2018 est.)
permanent pasture: 0% (2018 est.)
forest: 0% (2018 est.)
other: 100% (2018 est.)
Government
Country name
conventional long form: British Indian Ocean Territory
conventional short form: none
abbreviation: BIOT
etymology: self-descriptive name specifying the territory's affiliation and location
Dependency status
overseas territory of the UK; administered by a commissioner, resident in the Foreign, Commonwealth, and Development Office in London
Capital
name: often regarded as being on Diego Garcia
geographic coordinates: 7 18S, 12 24E
time difference: UTC+6 (12 hours ahead of Washington, DC, during Standard Time)
Constitution
history: British Indian Ocean Territory (Constitution) Order 2004
Legal system
the laws of the UK apply where applicable
Executive branch
chief of state: King CHARLES III (since 8 September 2022)
head of government: Commissioner Paul CANDLER (since 8 July 2021); Administrator Balraj DHANDA; note - both reside in the UK and are represented by Commander Colvin OSBORN, RN, Officer commanding British Forces on Diego Garcia (since January 2022)
cabinet: NA
elections/appointments: the monarchy is hereditary; commissioner and administrator appointed by the monarch
Diplomatic representation in the US
none (overseas territory of the UK)
Diplomatic representation from the US
embassy: none (overseas territory of the UK)
Flag description
white with six blue wavy horizontal stripes; the flag of the UK is in the upper hoist-side quadrant; the striped section bears a palm tree and yellow crown (the symbols of the territory) centered on the outer half of the flag; the wavy stripes represent the Indian Ocean; although not officially described, the six blue stripes may stand for the six main atolls of the archipelago
National anthem
note: as an overseas territory of the United Kingdom, "God Save the King" is official (see United Kingdom)
Economy
Economic overview
small island territory economy; economic activity mainly on Diego Garcia with national military installations; recently settled disputes with Mauritius have increased oil exports; established marine reserve has limited commercial fishing
Exports - partners
Singapore 69%, United States 10%, Canada 5%, Ireland 4%, Saudi Arabia 2% (2021)
Exports - commodities
tuna and other fish, computers, integrated circuits, diamonds, jewelry (2021)
Imports - partners
Singapore 64%, United States 22%, Panama 4%, Ireland 3%, Bulgaria 1% (2021)
Imports - commodities
inedible fish and animal products, aluminum structures, cement, boat propellers, packaged medicines (2021)
Exchange rates
the US dollar is used
Communications
Telecommunication systems
general assessment: separate facilities for military and public needs are available (2018)
domestic: all commercial telephone services are available, including connection to the Internet (2018)
international: country code (Diego Garcia) - 246; landing point for the SAFE submarine cable that provides direct connectivity to Africa, Asia and near-by Indian Ocean island countries; international telephone service is carried by satellite (2019)
Broadcast media
Armed Forces Radio and Television Service (AFRTS) broadcasts over 3 separate frequencies for US and UK military personnel stationed on the islands
Communications - note
Diego Garcia hosts one of four dedicated ground antennas that assist in the operation of the Global Positioning System (GPS) navigation system (the others are on Kwajalein (Marshall Islands), at Cape Canaveral, Florida (US), and on Ascension Island (Saint Helena, Ascension, and Tristan da Cunha))
Transportation
Airports - with paved runways
1
note: paved runways have a concrete or asphalt surface but not all have facilities for refueling, maintenance, or air traffic control; the length of a runway required for aircraft to safely operate depends on a number of factors including the type of aircraft, the takeoff weight (including passengers, cargo, and fuel), engine types, flap settings, landing speed, elevation of the airport, and average maximum daily air temperature; paved runways can reach a length of 5,000 m (16,000 ft.), but the “typical” length of a commercial airline runway is between 2,500-4,000 m (8,000-13,000 ft.)
Roadways
note: short section of paved road between port and airfield on Diego Garcia
Ports and terminals
major seaport(s): Diego Garcia
Military and Security
Military and security forces
no regular military forces
Military - note
defense is the responsibility of the UK; in November 2016, the UK extended the US lease on Diego Garcia until December 2036
Transnational Issues
Disputes - international
Mauritius and Seychelles claim the Chagos Islands; negotiations between 1971 and 1982 resulted in the establishment of a trust fund by the British Government as compensation for the displaced islanders, known as Chagossians, who were evicted between 1967-73; in 2001, the former inhabitants of the archipelago were granted UK citizenship and the right of return; in 2006 and 2007, British court rulings invalidated the immigration policies contained in the 2004 British Indian Ocean Territory Constitution Order that had excluded the islanders from the archipelago; in 2008, a House of Lords' decision overturned lower court rulings, once again denying the right of return to Chagossians; in addition, the UK created the world's largest marine protection area around the Chagos islands prohibiting the extraction of any natural resources therein