Chagos Archipelago

The Chagos Archipelago or Chagos Islands (formerly Bassas de Chagas, and later the Oil Islands) is a group of seven <a href="/facts/Atoll/cPyQIzVS">atolls</a> comprising more than 60 islands in the <a href="/facts/Indian_Ocean/Kv0crwKG">Indian Ocean</a> about 500 kilometres (310 mi) south of the <a href="/facts/Maldives/sC2HeXby">Maldives</a> archipelago. This chain of islands is the southernmost <a href="/facts/Archipelago/50BeC9tl">archipelago</a> of the <a href="/facts/Chagos%25E2%2580%2593Laccadive_Ridge/l7mofs1D">Chagos–Laccadive Ridge</a>, a long <a href="/facts/Submarine_mountain_range/CpxjBEjf">submarine mountain range</a> in the <a href="/facts/Indian_Ocean/Kv0crwKG">Indian Ocean</a>. In its north are the <a href="/facts/Salomon_Islands/UURhPTHt">Salomon Islands</a>, <a href="/facts/Nelsons_Island/z1VMzmeH">Nelsons Island</a> and <a href="/facts/Peros_Banhos/JfClUzxv">Peros Banhos</a>; towards its south-west are the <a href="/facts/Three_Brothers%2c_Chagos/7GCvq2tz">Three Brothers</a>, <a href="/facts/Eagle_Islands/JRxIw5fY">Eagle Islands</a>, <a href="/facts/Egmont_Islands/1tHKCkX9">Egmont Islands</a> and <a href="/facts/Danger_Island%2c_Great_Chagos_Bank/Buqqjh1W">Danger Island</a>; southeast of these is <a href="/facts/Diego_Garcia/7VGEWUYa">Diego Garcia</a>, by far the largest island. All are low-lying atolls, save for a few extremely small instances, set around <a href="/facts/Lagoon/IBp4ez2D">lagoons</a>.
From 1715 to 1810, the Chagos Islands were part of France's <a href="/facts/List_of_French_possessions_and_colonies/T1pTy70Y">Indian Ocean possessions</a>, administered through <a href="/facts/Isle_de_France_(Mauritius)/F4Bt3y3A">Isle de France</a> – which was a <a href="/facts/French_colonial_empire/IRauBDs1">colony of France</a> (later renamed as <a href="/facts/Mauritius/lVUARna5">Mauritius</a>). Under the <a href="/facts/Treaty_of_Paris_(1814)/aFeCF7sA">Treaty of Paris</a> in 1814, France ceded Isle de France and the Chagos Islands to the <a href="/facts/United_Kingdom/kuPAILt2">United Kingdom</a>.
In 1965, the United Kingdom split its administration of the Chagos Archipelago away from Mauritius and into the <a href="/facts/British_Indian_Ocean_Territory/jD0nq0Ht">British Indian Ocean Territory</a> (BIOT). The islands were formally established as an overseas territory of the United Kingdom on 8 November 1965. 
The British government separated the Chagos Archipelago from Mauritius, creating a new colony in Africa, the British Indian Ocean Territory (BIOT). To avoid accountability to the United Nations for its continued colonial rule, the UK falsely claimed that the Chagos had no permanent population.
The Chagos Islands had been home to the <a href="/facts/Chagossians/zcaQU7dx">Chagossians</a>, a <a href="/facts/Bourbonnais_Creole/UYEwN1BJ">Bourbonnais Creole</a>–speaking people, until the United Kingdom <a href="/facts/Expulsion_of_the_Chagossians/UzEh849M">expelled them from the archipelago</a> at the request of the <a href="/facts/United_States/P0sCdLe5">United States</a> between 1967 and 1973 to allow the United States to build <a href="/facts/Naval_Support_Facility_Diego_Garcia/5gvjnYd1">Naval Support Facility Diego Garcia</a>, which operates under a special agreement allowing significant US military presence. The main forcible removal of Diego Garcia’s population took place in July and September 1971. Since 1971 only the atoll of Diego Garcia has been inhabited, and only by employees of the military including civilian contracted personnel. Since being expelled, Chagossians have been prevented from entering the islands. 
Mauritius was engaged in a <a href="/facts/Chagos_Archipelago_sovereignty_dispute/h64hjmbq">sovereignty dispute</a> with the UK, claiming the Chagos Archipelago as part of Mauritius. The <a href="/facts/International_Court_of_Justice/7q8I7oSs">International Court of Justice</a> (ICJ) and the <a href="/facts/International_Tribunal_for_the_Law_of_the_Sea/EuCXy0Wc">International Tribunal for the Law of the Sea</a> both stated that the UK had an obligation to return the islands to Mauritius. In October 2024, the British government announced it would transfer the Chagos Islands to Mauritius subject to finalisation of a treaty. The transfer agreement was signed on 22 May 2025, with the provision that the island of Diego Garcia would be leased back to the UK for at least 99 years. The UK government expects the treaty to be ratified near the end of 2025.

Chagos Archipelago open-in-new

Chagos Archipelago