British Indian Ocean Territory

British Indian Ocean Territory is a territory in the Africa card group. UK-administered; sovereignty disputed by Mauritius. The 2025 treaty is subject to entry into force.

Find British Indian Ocean Territory

● Administrative center · Gold highlights this card’s area.
Map: Natural Earth. Boundaries show geographic context, not a position on sovereignty. Small islands may use enlarged markers.

At a glance

Administrative center: Diego Garcia
Languages: English
Currency: United States dollar (USD)
Population: No permanent resident civilian communityMilitary personnel and contractors are not a national resident-population series.
Area: 60 km²23 square miles
Status: UK-administered; sovereignty disputed by Mauritius. The 2025 treaty is subject to entry into force.

British Indian Ocean Territory in context

Africa and its surrounding islands. The dot marks Diego Garcia; the mapped territory is highlighted in gold.

Natural Earth · locator map

Geography & languages

Physical geography

Low coral islands and atolls in the central Indian Ocean, south of the Maldives.

Languages

Languages used in public life include English.

Location

Low coral islands and atolls in the central Indian Ocean, south of the Maldives.

Flag

The territory’s flag combines the Union Flag, blue-and-white waves, a palm tree and a crown.

Sources: UK government · territory profile · UK Parliament · treaty status, 2026

History & status

The UK created the British Indian Ocean Territory in 1965 by separating the Chagos Archipelago from Mauritius. Chagossians were forcibly displaced as the Diego Garcia military base was developed. A UK–Mauritius treaty signed in 2025 proposes a change in sovereignty, but signature and entry into force are distinct steps.

1965
The British Indian Ocean Territory is created
1960s–1970s
Chagossians are forcibly displaced
2025
The UK and Mauritius sign a treaty on the archipelago

Sources: UK government · territory profile · UK Parliament · treaty status, 2026

Economy

Main activities

Economic activity centers on the military facilities on Diego Garcia and their support services.

Sources: UK government · territory profile · UK Parliament · treaty status, 2026

Population

There is no permanent resident civilian community. Military personnel and civilian contractors work on Diego Garcia.

Sources: UK government · territory profile · UK Parliament · treaty status, 2026

Government

British Overseas Territory administered through a commissioner. The 2025 UK–Mauritius treaty provides for Mauritian sovereignty and continued UK operation of Diego Garcia’s base, subject to entry into force. UK parliamentary reporting in 2026 describes the implementation legislation as paused.

Sources: UK government · territory profile · UK Parliament · treaty status, 2026

Knowledge check

Three questions about British Indian Ocean Territory.

QUESTION 1 OF 3

In which year did this event occur in British Indian Ocean Territory: The UK and Mauritius sign a treaty on the archipelago?

Sources & notes

Sources: UK government · territory profile · UK Parliament · treaty status, 2026

Prepared 24 September 2026. World Bank series: SP.POP.TOTL (persons) and NY.GDP.MKTP.KD (constant 2015 US dollars); downloaded 24 September 2026, provider update 13 July 2026. UNDP values use the 2025 report and 2023 observation year. These are dated statistical snapshots, not live population or economic counters.

Maps use Natural Earth geographic data. Background geography, flag descriptions and selected historical facts use archived public-domain CIA World Factbook profiles, supplemented by the sources linked above. The Factbook is no longer updated; dated statistics here come from the separately named providers.