3°48′N 73°24′E / 3.800°N 73.400°E
The Chagos–Lakshadweep Ridge (CLR), also known as the Chagos–Lakshadweep Plateau, is a prominent volcanic ridge and oceanic plateau extending between the Northern and the Central Indian Ocean. Laccadive is an anglicized adaptation of the word Lakshadweep which means "One Hundred Thousand Islands". After 1973, the Indian government de-recognized the colonial word "Laccadive " and renamed it "Lakshadweep" as per local lingua franca.
The Chagos Archipelago (/ˈtʃɑːɡəs, -ɡoʊs/, also UK: /ˈtʃeɪɡɒs/) or Chagos Islands (formerly Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives archipelago. This chain of islands is the southernmost archipelago of the Chagos–Laccadive Ridge, a long submarine mountain range in the Indian Ocean. In its north are the Salomon Islands, Nelsons Island and Peros Banhos; towards its south-west are the Three Brothers, Eagle Islands, Egmont Islands and Danger Island; southeast of these is Diego Garcia, by far the largest island. All are low-lying atolls, save for a few extremely small instances, set around lagoons.
From 1715 to 1810, the Chagos Islands were part of France's Indian Ocean possessions, administered through Isle de France – which was a colony of France (later renamed as Mauritius). Under the Treaty of Paris in 1814, France ceded Isle de France and the Chagos Islands to the United Kingdom.
Diego Garcia is the largest island of the Chagos Archipelago. It has been used as a joint UK–U.S. military base since the 1970s, following the expulsion of the Chagossians by the UK government. The Chagos Islands is a British overseas territory, though a treaty to transfer sovereignty from the UK to Mauritius was signed on 22 May 2025, with a provision that the military base at the island would remain under British control for at least 99 years. The agreement may be renewed for an additional 40 years after the initial 99-year period, and for an additional period thereafter.
Located just south of the equator in the central Indian Ocean, Diego Garcia lies 3,535 km (2,197 mi) east of Tanzania, 2,984 km (1,854 mi) east-southeast of Somalia, 726 km (451 mi) south of the Maldives, 1,796 km (1,116 mi) southwest of India, 2,877 km (1,788 mi) west-southwest of Sumatra, 4,723 km (2,935 mi) northwest of Australia, and 2,112 km (1,312 mi) northeast of Mauritius Island. Diego Garcia is part of the Chagos-Laccadive Ridge, an underwater mountain range that includes the Lakshadweep, the Maldives, and the other 60 small islands of the Chagos Archipelago. The island observes UTC+6 year-round.