Chagos Archipelago

Chagos Archipelago

[chah-gohs, -guhs]
Chagos Archipelago: see British Indian Ocean Territory.

The Chagos Archipelago (formerly, Oil Islands) is a group of seven atolls comprising more than 60 individual tropical islands roughly in the centre of the Indian Ocean.

The Chagos lies about 500 km (300 miles) due south of the Maldives, its nearest neighbour, 1600 km (1000 miles) southwest of India, half way between Tanzania and Java.

The Chagos group is a combination of different coralline structures topping a submarine ridge running southwards across the centre of the Indian Ocean, formed by volcanoes above the Réunion hotspot. Unlike in the Maldives there is not a clearly discernible pattern of arrayed atolls, which makes the whole archipelago look somewhat chaotic. Most of the coralline structures of the Chagos are submerged reefs.

Officially part of the British Indian Ocean Territory, the Chagos were home to the Chagossians for more than a century and a half until their forced expulsion in the 1960s by the United Kingdom and United States.


The entire land area of the islands is a mere 63.17 km², with the largest island, Diego Garcia, having an area of 27.20 km². The total area, including lagoons within atolls, however, is more than 15,000 km², of which 12,642 km² are accounted by the Great Chagos Bank, the second largest atoll structure of the world (after the completely submerged Saya de Malha Bank). The shelf area is 20,607 km², and the Exclusive Economic Zone, which borders to the corresponding zone of the Maldive Islands in the north, has an area of 636,600 km² (including territorial waters).

The largest individual islands are Diego García (27.20 km²), Eagle (Great Chagos Bank, 2.45 km²), Île Pierre (Peros Banhos, 1.50 km²), Eastern Egmont (Egmont Islands, 1.50 km²), Île du Coin (Peros Banhos, 1.28 km²) and Île Boddam (Salomon Islands, 1.08 km²).

The number of atolls in the Chagos Islands is given as four or five in most sources, plus two island groups and two single islands, mainly because it is not recognized that the Great Chagos Bank is a huge atoll structure (including those two island groups and two single islands), and because it is not recognized that Blenheim Reef has islets or cays above or just reaching the high water mark.

In addition to the seven atolls with dry land reaching at least the high water mark, there are nine reefs and banks, most of which can be considered permanently submerged atoll structures. They are listed in the table from north to south:

(alternate name)
type Area (km²) number
of islands
Land Total
0 unnamed bank submerged bank 3
1 Colvocoresses Reef submerged atoll 10
2 Speakers Bank unvegetated atoll >0 582 1)
3 Blenheim Reef (Baixo Predassa) unvegetated atoll 0.3 37 4
4 Benares Shoals submerged reef 2
5 Peros Banhos atoll 13 503 32
6 Salomon Islands atoll 5 36 11
7 Victory Bank submerged atoll 21
8a Nelsons Island parts of mega-atoll
Great Chagos Bank
0.81 12642 1
8b Three Brothers (Trois Freres) 0.37 3
8c Eagle Islands 2.63 3
8d Danger Island 0.66 1
9 Egmont Islands atoll 4 29 7
10 Cauvin Bank submerged atoll 12
11 Owen Bank submerged bank 4
12 Pitt Bank submerged atoll 1317
13 Diego Garcia atoll 30 174 42)
14 Ganges Bank submerged atoll 30
15 Wight Bank 3
16 Centurion Bank 25
Chagos Archipelago Archipelago 63.17 15427 64 04°54' to 07°39'S
70°14' to 72°37' E
1) a number of drying sand cays
2) main island and three islets at the northern end


The main natural resources of the area are coconuts, and fish and the licensing of commercial fishing provides an annual income of about two million dollars for the British Indian Ocean Territory authorities.

All economic activity is concentrated on the largest island of Diego Garcia, where joint UK-US military facilities are located. Construction projects and various services needed to support the military installations are done by military and contract employees from the UK, Mauritius, the Philippines, and the US. There are currently no industrial or agricultural activities on the islands. All the water, food and other essentials of daily life are shipped to the island. An independent feasibility study led to the conclusion that resettlement would be "costly and precarious". Another feasibility study, commissioned by organisations supporting resettlement, found that resettlement would be possible at a cost to the British taxpayer of £25 million. If the Chagossians return, they plan to re-establish copra production and fishing, and to begin the commercial development of the islands for tourism.


Tropical oceanic climate; hot and humid but moderated by trade winds. Climate is characterised by plenty of sunshine, warm temperatures, showers and light breezes. December through February is considered the rainy season (summer monsoon); typical weather conditions include light west-northwesterly winds and warmer temperatures with more rainfall. June through September is considered the drier season (winter), characterised by moderate south-easterly winds, slightly cooler temperatures and less rainfall. The annual mean rainfall is 2600 mm (100 inches), varying from 105 mm (4 inches) during August to 350 mm (14 inches) during January.


Maldivian mariners knew the Chagos Islands well. In Maldivian lore they are known as Fōlhavahi or Hollhavai (the latter name in the closer Southern Maldives). According to Southern Maldivian oral tradition, traders and fishermen were occasionally lost at sea and got stranded in one of the islands of the Chagos. Eventually they were rescued and brought back home. However, these islands were judged to be too far away from the Maldives to be settled permanently by Maldivians. Thus for many centuries the Chagos were ignored by their northern neighbors.

The first European explorer to spot the Chagos was Vasco da Gama in the early 16th century. Portuguese seafarers named the group and some of the Atolls, but they never made these islands part of their seaborne empire. They judged this lonely and isolated group to be economically and politically uninteresting.

The French were the first to lay a claim on the Chagos after they settled Réunion and Ile de France (later renamed Mauritius).

On 27 April 1786 the Chagos Isands and Diego Garcia were claimed for Britain. However, the territory was ceded to the United Kingdom by treaty only after Napoleon's defeat, in 1814. On 31 August 1903 the Chagos Archipelago was administratively separated from the Seychelles and attached to Mauritius.

The islands were retained as part of the British Indian Ocean Territory when Mauritius gained independence. Since 1976, the archipelago has been coterminous with the British Indian Ocean Territory, but it is also claimed by Mauritius and Seychelles.

The archipelago's first inhabitants arrived in the 18th century. These were the lepers of Ile de France (Mauritius) who were brought there in the second half of the 1700s. Soon after, a plan was drawn up by the French to settle the Chagos and make them profitable. Workers for a massive French project to establish coconut plantations and produce oil were sent from Ile de France (Mauritius) and settled in some of the largest islands. Consequently, in some maps of the time the Chagos are known as the "Oil Islands". Most of these workers were of African origin, but it is likely that there were also a few South Indians among them. The supervisors of the plantations were probably Frenchmen and the workers were probably little more than slaves, but very little has been recorded about conditions on the islands during that time.

By the mid-20th century the oil plantations had largely failed, but the original workers and their families had settled some of the largest islands and survived there. The islanders were known as the Ilois (one French Creole word for "islanders") and they numbered almost 2,000. They were of mixed African and South Asian descent and lived very simple, spartan lives in their isolated archipelago. Few remains of their culture have been left, except for the ruins of a few dwellings and a stone church that can still be seen in Diego Garcia.

Suddenly, between 1967 and 1971, the entire population was forcibly removed from the islands and relocated to Mauritius to make way for a joint United States-United Kingdom military base on Diego Garcia. Apparently, the displaced people received an initial funding of some £650,000 for their rehousing from the British Government, but individual islanders saw little of those funds and ended up living in a slum in Mauritius. After negotiations in the late 1970s and early 1980s, the Government agreed to pay a further £4 million to the Chagossians. The Government says the total sums paid to the Chagossians amounts to £14.5 million in today's prices. Attempts by the Chagossians to secure additional compensation to this were dismissed by the High Court and Court of Appeal in 2003 and 2004 (

In the Chagos, the houses the Chagossians had abandoned fell slowly into ruin. Now the vegetation has taken over and in some islands it is difficult to discern where the village once had been. Yachtsmen passing through the archipelago often try to find the ruins and are unsuccessful.

Currently, the only human structures on the islands are located in the joint defence and naval support facility on Diego Garcia. Other uninhabited islands, especially in the Salomon group, are common stopping points for long-distance yachtsmen travelling from Southeast Asia to the Red Sea or the coast of Africa, although a permit is required to visit the outer islands.

For more information on the expulsion of the islanders and the court case, please read the article on Diego Garcia.


The most high profile aspect of Chagos Island politics relates to the continued uncertainty as to the future of the former inhabitants of the islands who were evicted in the 1960s and 1970s as part of an arrangement between the United Kingdom and the United States to establish a military establishment on the island of Diego Garcia. The islanders' plight has been well documented, including a documentary produced by investigative journalist John Pilger, entitled "Stealing a Nation", which won the British Royal Television Society Best Documentary Award in 2004.

In 2000, the English High Court ruled that a local Ordinance made by the Commissioner of the British Indian Ocean Territory exiling the islanders was unlawful, a decision which was accepted by the British Foreign Secretary, Robin Cook. Subsequent efforts by the Chagossians to obtain further compensation payments were dismissed by the High Court and Court of Appeal, who held that the compensation paid had been fair and lawful. Following the conclusion of the compensation cases, the British Government attempted to achieve the same objective through use of Orders in Council enacted under the royal prerogative, which is the only means short of an Act of Parliament by which legislation can be enacted for the Territory. These Orders in Council were found in part to be unlawful by the High Court. The UK government appealed the ruling, but on 23 May 2007 the Appeal Court dismissed the appeal saying that the methods used to stop the Chagos families to return to the islands were "unlawful" and "an abuse of power". The Government has been granted leave to appeal to the House of Lords on the condition that they undertake to pay the costs of the respondents and the case is set down for argument in June 2008.

Thus, although these court rulings make it legal for these people to return to all islands other than Diego Garcia - which is currently the only island in the group used for military purposes - it seems unlikely that resettlement of the islands will commence until legal proceedings have been concluded.

If these court rulings are upheld, the long term future of the archipelago appears uncertain. In the medium term the US-UK joint use of Diego Garcia for defence purposes is by treaty currently set to expire in 2016, although both Governments have the option of extending the lease for another 20 years if considered necessary.

Beyond this date, it appears from statements made by Mauritius to the United Nations Human Rights Committee that the United Kingdom has undertaken to cede the islands to Mauritius once they are no longer required for defence purposes. This could potentially result in a conflict between this commitment and potential claims of a right to self-determination by some of the Chagossians.


The inhabitants of Chagos were speaking Ilois, a French Creole which has not been properly researched from the linguistic point of view.

The island names are a striking combination of Portuguese, French, English and Creole names. Few places in the world can display such variety of origins in local nomenclature.



  • Pilger, John Freedom Next Time. Bantam Press. ISBN 0593055527. Chapter 1: Stealing a Nation pp19 - 60
  • Rao, Padma, "Der Edikt der Königin," Der Spiegel 5 December 2005, pp. 152-4.
  • Xavier Romero-Frias, The Maldive Islanders, A Study of the Popular Culture of an Ancient Ocean Kingdom. Barcelona 1999, ISBN 84 7254 801 5


See also

External links

Search another word or see chagos archipelagoon Dictionary | Thesaurus |Spanish
Copyright © 2015, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature