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British Indian Ocean Territory

Formerly part of the British Crown Colony of Mauritius, the British Indian Ocean Territory (BIOT) became a UK overseas territory in 1965. Some islands were later transferred to the Seychelles when it gained independence in 1976. Since then, BIOT has only consisted of the six main groups in the Chagos Archipelago. The largest and most southerly island, Diego Garcia, is inhabited and serves as a joint UK-US naval support facility. It also hosts one of four dedicated ground antennas for operating the Global Positioning System (GPS). The US Air Force has a telescope array on Diego Garcia as part of the Ground-Based Electro-Optical Deep Space Surveillance System (GEODSS), which tracks orbital debris that can be dangerous to spacecraft and astronauts.


The British Indian Ocean Territory (BIOT) was established in 1965 as an overseas territory of the UK. Originally part of the British Crown Colony of Mauritius, it now solely comprises the Chagos Archipelago, with Diego Garcia being its largest and only inhabited island. This strategically significant territory has been at the center of various international disputes, particularly concerning the rights of the displaced Chagossians.


Official Name: British Indian Ocean Territory (BIOT)
Date of Formation: 1965
Capital: None
Population: Approximately 3,000 (mostly UK and US military personnel and contractors)
Total Area: 23 sq miles / 60 sq km
Population Density: Not applicable
Languages: English
Religions: Various
Ethnic Origin: Primarily military personnel and contractors
Government: Overseas territory of the UK
Currency: US Dollar (USD)
Literacy Rate: Not applicable

Google Maps

Google Maps provides detailed views of the British Indian Ocean Territory, particularly Diego Garcia, showcasing its strategic military facilities and the unique geographical layout of the Chagos Archipelago.


The British Indian Ocean Territory (BIOT), known for its tropical marine climate, presents several climatic and environmental characteristics that contribute to its distinctiveness in the Indian Ocean:

  1. Tropical Marine Climate: The BIOT experiences a typical tropical marine climate characterized by relatively uniform temperatures throughout the year. The average daily temperatures usually range between 25°C and 30°C (77°F and 86°F). This stable temperature range is a hallmark of tropical oceanic climates.
  2. Humidity and Rainfall: The region is known for its high humidity levels, often around 80% or higher. Rainfall is also a significant feature, with the wettest months being between May and September. The annual rainfall can vary, but it typically ranges from 2000 mm to 2500 mm.
  3. Trade Winds Influence: The climate is significantly influenced by the trade winds. From November to March, the northeast monsoon prevails, while from May to September, the southeast monsoon dominates. These winds moderate the temperatures and contribute to the seasonal rainfall patterns.
  4. Cyclonic Activity: The BIOT lies outside the main cyclone belt of the Indian Ocean but can occasionally be affected by tropical cyclones and storms, especially during the transition periods between the monsoons.
  5. Marine Environment and Coral Reefs: The tropical marine climate supports a rich and diverse marine ecosystem. The BIOT is known for its extensive coral reefs, which are among the most pristine in the world. These reefs support many marine life, including several endangered species.
  6. Satellite Imagery Accessibility: The archipelago’s location and clear waters make it an ideal subject for satellite imagery analysis, which is easily accessible through platforms like Google Maps. This allows for a detailed observation of the atolls, reef structures, and the overall geography of the region.
  7. Climate Change Impacts: Like many tropical marine environments, the BIOT faces challenges due to climate change. Rising sea temperatures concern coral reefs, leading to bleaching events. Additionally, the rise in sea level poses a long-term threat to the low-lying islands of the territory.
  8. Conservation Efforts: Recognizing the region’s ecological importance, significant efforts have been made to conserve its marine biodiversity. The Chagos Archipelago, part of the BIOT, has been declared a marine protected area, making it one of the largest no-take marine reserves in the world.
  9. Human Impact and Research: The BIOT is critical in environmental and climate research despite being largely uninhabited. The undisturbed nature of its ecosystems provides valuable insights into the functioning of tropical marine environments and the impacts of global environmental changes.

In summary, the British Indian Ocean Territory’s climate is characterized by its tropical nature, moderated by trade winds, with significant implications for its marine ecosystem and environmental conservation efforts. The area’s accessibility through satellite imagery enhances its value for research and education about tropical marine environments.


The British Indian Ocean Territory (BIOT), with its unique geographical features, is a significant entity in the Indian Ocean. Here’s an extended overview incorporating deeper statistics and information about the surrounding countries:

  1. Location and Proximity: Situated in the central Indian Ocean, the BIOT is about halfway between the eastern coast of Africa and Indonesia. This location makes it strategically significant, especially considering major maritime routes nearby.
  2. Geographical Composition: The territory is an archipelago comprising over 1,000 individual islands grouped into seven atolls. The largest atoll and perhaps the most well-known is the Great Chagos Bank, which includes many small islands and large submerged reefs.
  3. Elevation and Topography: The islands are characteristically flat and low-lying, with most of them not exceeding two meters above sea level. This low elevation makes them particularly vulnerable to rising sea levels and storm surges. The highest natural point in the BIOT is on Diego Garcia, which is about 15 meters above sea level.
  4. Chagos-Laccadive Ridge: The archipelago sits atop the Chagos-Laccadive Ridge, an extensive submarine mountain range in the Indian Ocean. This ridge is of volcanic origin and is part of a vast undersea plateau, including the Maldives and the Laccadive Islands.
  5. Surrounding Countries:
  • To the north, the closest country is the Maldives, also situated along the Chagos-Laccadive Ridge.
  • To the west, the nearest mainland is Africa, particularly the East African countries like Tanzania and Mozambique.
  • To the east, the Indonesian island of Sumatra is a significant neighboring landmass.
  • To the south, there is the vast expanse of the Indian Ocean, with Antarctica being the nearest continent in the far south.
  1. Marine Biodiversity: The waters surrounding the islands are known for their rich marine biodiversity. They are home to extensive coral reefs, which are some of the least disturbed and most resilient to climate change in the world.
  2. Environmental Concerns: Given their low elevation and the threats posed by climate change, the islands face significant risks. Rising sea levels, increased frequency of severe weather events, and ocean acidification are major concerns.
  3. Human History and Impact: Historically, the Chagos Archipelago was inhabited, but the population was relocated in the 1960s and 1970s to establish a military base on Diego Garcia, the largest island. The environmental impact of human activities, primarily related to the military base, has been a subject of study and concern.
  4. Legal and Political Status: The BIOT is a British Overseas Territory, and its sovereignty has been disputed, particularly with Mauritius, which claims the territory. International legal and political decisions continue to influence the status and future of the BIOT.
  5. Scientific Research: The archipelago’s isolated location and relatively undisturbed environment make it an important site for scientific research, particularly in the fields of marine biology, climate science, and oceanography.

The British Indian Ocean Territory’s strategic location, unique geological and ecological characteristics, and the political and legal complexities surrounding it make it a particularly interesting region for geographical, environmental, and geopolitical studies.

Resources and Land Use

Natural resources in the BIOT are limited, primarily comprising coconuts, fish, and sugarcane. The land use is predominantly for military purposes, particularly on Diego Garcia, with very little agricultural activity.

Population Data

There are no indigenous inhabitants in the BIOT. The current population comprises approximately 3,000 UK and US military personnel and civilian contractors residing on Diego Garcia.

Economic Data

The economy of the British Indian Ocean Territory is mainly driven by the military installations on Diego Garcia. The island’s strategic location has led to significant defense and military operations development.

Drinking Water Source

Freshwater resources are limited in the BIOT, with most water requirements likely met through desalination and importation, given the presence of military bases.

Population, Median Age, Migration, and Citizenship

These demographic details are primarily relevant to the military and contractor personnel stationed on Diego Garcia, with a transient and diverse population profile.

Average Number of Childbirths

Given the nature of the population of Diego Garcia, the average number of childbirths is not a significant statistic for the BIOT.

Is this country a Safe Destination?

Safety in the BIOT is closely linked to its status as a military territory. While it may not have typical civilian safety concerns, its strategic importance implies stringent security measures.

Healthcare and Infectious Diseases

Healthcare facilities in the BIOT are likely geared towards serving the military’s and associated personnel’s needs, with standard precautions for tropical infectious diseases.

Natural Hazards

Due to its geographical location, the BIOT is notably free from major natural hazards like cyclones.

The Flag and Other Symbols

The flag of the British Indian Ocean Territory features the Union Jack along with the territory’s emblem, symbolizing its connection to the UK.


As an overseas territory of the UK, the BIOT is governed by laws applicable from the UK, without a separate constitution.

The legal system of the BIOT follows that of the United Kingdom, under the oversight of a Commissioner based in the UK.

About the Unemployment Rate, Labor Force, and Poverty Line

These economic indicators are not typically relevant for the BIOT, given its unique status as a military base with no permanent civilian population.

About the Budget and Central Government Debt

The UK government manages economic aspects such as budget and debt, with expenditures largely focused on military and administrative operations.

Inflation Rate and Prime Lending Rate

Inflation and lending rates are not significant economic measures in the context of the BIOT, as the territory operates under the economic system of the UK and US military establishments.

Export/Import Partners and Data

The BIOT has limited economic activity in terms of exports and imports, with most trade related to military supplies and logistical support.

Renewable Energies Used

Information on renewable energy usage in the BIOT is not prominently available, but it’s likely that the military installations utilize some form of sustainable energy source.

Telecommunication Data, Calling Code

Telecommunication in the BIOT is primarily for military use, with Diego Garcia having its own country code (+246) and internet country code (.io).

Transport Infrastructure

Transport in the BIOT is centered around military requirements, with Diego Garcia having an airfield and port facilities to support military operations.

More Interesting Facts

Did You Know?

  • Unique Legal Status: The British Indian Ocean Territory is one of the few British Overseas Territories without a permanent population. This unique status has been the subject of international legal disputes, especially with Mauritius, which claims sovereignty over the territory.
  • Marine Biodiversity Haven: The waters around the BIOT are among the world’s richest marine biodiversity areas. They host over 1,000 species of fish, around 200 species of coral, and are a critical habitat for the endangered green and hawksbill turtle.
  • Largest Marine Reserve: In 2010, the British government declared the territorial waters of the BIOT as a marine reserve. Covering an area of about 640,000 square kilometers, it is one of the largest marine protected areas in the world.
  • Strategic Military Location: The largest island in the BIOT, Diego Garcia, is a key military base for the United States and the United Kingdom. Its strategic location has played a significant role in various military operations since the Cold War era.
  • Astronomical Phenomena Observations: The BIOT’s remote location and clear skies make it ideal for observing space and astronomical phenomena. In 1965, a total solar eclipse was observed from the territory, providing valuable data for scientific research.
  • Ancient Volcanic Origin: The islands sit atop the Chagos-Laccadive Ridge, a submarine mountain range formed by volcanic activity over 60 million years ago. This geological feature connects the territory with the Maldives to the north.
  • Historical Coconut Plantations: In the past, copra (dried coconut kernel) was the main product of the Chagos Islands, with plantations established during the 18th and 19th centuries. These were operated primarily by contract laborers from India and Africa.
  • Environmental Monitoring Site: Due to its isolation and pristine environment, the BIOT is an important site for global environmental monitoring, including studies on climate change and its impact on coral reefs and sea levels.
  • Rare Bird Species: The territory is home to the Chagos Archipelago’s endemic bird, the Chagos Bittern. This bird species is of significant interest to ornithologists and conservationists.
  • Underwater Mountains and Trenches: The territory’s underwater landscape includes some of the Indian Ocean’s deepest trenches and underwater mountains, offering unique opportunities for deep-sea exploration and research.

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