The British Indian Ocean Territory (BIOT) is a British overseas territory situated in the Indian Ocean. It is located in the Chagos Archipelago, which is a group of islands that lie approximately halfway between East Africa and Indonesia. The territory covers an area of around 640,000 square kilometers (250,000 square miles), and it is largely uninhabited, with the exception of military personnel and their families.

The Chagos Archipelago was part of the British colony of Mauritius until 1965, when it was detached from Mauritius in exchange for British support for the independence of Mauritius. The Chagos Islands were then established as a separate British colony, which later became the British Indian Ocean Territory in 1965.

The territory is home to the US Navy's Naval Support Facility Diego Garcia, which is located on the island of Diego Garcia. The base is used to support military operations in the Middle East and Asia. The US lease for the base is set to expire in 2036, although the UK government has stated that it has no intention of returning the territory to Mauritius.

The sovereignty of the British Indian Ocean Territory is disputed by Mauritius, which claims the islands as part of its territory. In 2019, the International Court of Justice issued an advisory opinion stating that the separation of the Chagos Archipelago from Mauritius was illegal, and that the UK should return the islands to Mauritius as soon as possible. The UK government, however, rejected the ruling, stating that the UK has no doubt about its sovereignty over the territory.

Geography
Area
total: 60 sq km
land: 60 sq km
water: 54,340 sq km

Climate
tropical marine; hot, humid, moderated by trade winds

Natural resources
coconuts, fish, sugarcane

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