View source for Diego Garcia

{{Short description|Island in the Indian Ocean}}
{{Other uses}}
{{Use dmy dates|date=August 2024}}
{{Use British English|date=August 2024}}
{{Infobox islands
| name               = Diego Garcia
| image_name         = diegogarcia.jpg
| image_caption      = Aerial photograph of Diego Garcia
| image_size         = 255px
| map                = 
| map_alt            = 
| map_width          = 255
| map_caption        = Location of Diego Garcia
| label              = 
| label_position     = 
| coordinates        = {{coord|7|18|48|S|72|24|40|E|display=inline,title}}
| location           = 
| archipelago        = [[Chagos&nbsp;Archipelago]]
| area_km2           = 30
| area_footnotes     = 
| rank               = 
| elevation_m        = 
| country_largest_city = 
| population         = 4,239<ref>{{cite web|url=http://www.fco.gov.uk/en/travel-and-living-abroad/travel-advice-by-country/country-profile/asia-oceania/british-indian-ocean-territory |title=Country Profile: British Indian Ocean Territory (British Overseas Territory) |publisher=Foreign and Commonwealth Office |date=12 April 2012 |access-date=21 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120620082359/http://www.fco.gov.uk/en/travel-and-living-abroad/travel-advice-by-country/country-profile/asia-oceania/british-indian-ocean-territory/ |archive-date=20 June 2012 }}</ref>
| population_as_of   = <!--?-->
| density_km2        = 
| waterbody          = [[Indian&nbsp;Ocean]]
| timezone1          = [[UTC+6]]
| module             = {{Designation list
| embed = yes
| designation1 = Ramsar
| designation1_date = 4 July 2001
| designation1_number = 1077<ref>{{cite web|title=Diego Garcia|website=[[Ramsar Convention|Ramsar]] Sites Information Service|url=https://rsis.ramsar.org/ris/1077|access-date=25 April 2018|archive-date=18 June 2024|archive-url=https://web.archive.org/web/20240618095717/https://rsis.ramsar.org/ris/1077|url-status=live}}</ref>}}
| disputed           = Yes
| country            = {{flag|United Kingdom}}
| country_admin_divisions_title = [[British Indian Ocean Territory]]
| country_admin_divisions = [[British Indian Ocean Territory]]
| country1           = 
| country1_admin_divisions_title = 
| country1_admin_divisions = 
}}

'''Diego Garcia''' ({{IPAc-en|d|i|ˈ|eɪ|.|ɡ|oʊ|_|ɡ|ɑɹ|ˈ|s|iː|ə}}<ref>{{cite dictionary|dictionary=Webster's New World College Dictionary 5th Digital Edition|title=Diego Garcia|url=https://www.collinsdictionary.com/dictionary/english/diego-garcia|publisher=HarperCollins}}</ref>) 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 are 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.<ref>{{Cite web |title=UK signs deal to hand over Chagos Islands and lease back military base for £101m a year|first1=Emily|last1=Atkinson|first2=Owen|last2=Amos|url=https://www.bbc.co.uk/news/live/clyvv04wk8zt |access-date=2025-05-22 |website=BBC News |language=en-GB}}</ref> The agreement may be renewed for an additional 40 years after the initial 99-year period, and for an additional period thereafter.<ref>{{Cite web |title=UK warned of threat from China when Chagos deal expires |url=https://www.politico.eu/article/uk-minister-china-chagos-island-david-lammy-deal/ |access-date=2025-06-27 |website=politico.eu |language=en}}</ref> The UK government expected the treaty to be ratified sometime in 2026.<ref>{{cite web|title=Chagos Islands deal risks security and marine protection, insider says|date=4 January 2026 |url-access= subscription|url=https://www.thetimes.com/uk/politics/article/chagos-islands-deal-risks-security-marine-protection-6sl8n9m2n|website=The Times |access-date=4 January 2026}}</ref> The [[International Convention on the Elimination of All Forms of Racial Discrimination#Committee on the Elimination of Racial Discrimination|UN Committee on the Elimination of Racial Discrimination]] has expressed "deep concern" at the terms of the deal.<ref>{{cite web|title=UN committee 'deeply concerned' by Chagos deal - and calls for ratification to be paused|url=https://news.sky.com/story/un-committee-deeply-concerned-by-chagos-deal-and-calls-for-ratification-to-be-paused-13481144|website=Sky |access-date=5 January 2026}}</ref>

Located just south of the equator in the central [[Indian Ocean]], Diego Garcia lies {{convert|3535|km|0|abbr=on}} east of [[Tanzania]], {{convert|2984|km|0|abbr=on}} east-southeast of [[Somalia]], {{convert|726|km|0|abbr=on}} south of the [[Maldives]], {{convert|1796|km|0|abbr=on}} southwest of [[India]], {{convert|2877|km|0|abbr=on}} west-southwest of [[Sumatra]], {{convert|4723|km|0|abbr=on}} northwest of [[Australia]], and {{convert|2112|km|0|abbr=on}} northeast of [[Mauritius#Mauritius Island|Mauritius Island]]. Diego Garcia is part of the [[Chagos–Laccadive Ridge]], an underwater mountain range<ref>{{NatGeo ecoregion|id=im0125|name=Maldives-Lakshadweep-Chagos Archipelago tropical moist forests|access-date=21 June 2012}}</ref> that includes the [[Lakshadweep]], the [[Maldives]], and the other 60 small islands of the Chagos Archipelago. The island observes [[UTC+6]] year-round.<ref name="USNWorldTimeChart">{{cite web |title=World Time Chart |url=https://www.cnic.navy.mil/navycni/groups/public/documents/document/cnicd_a095922.pdf |url-status=dead |archive-url=https://web.archive.org/web/20120126224933/http://www.cnic.navy.mil/navycni/groups/public/documents/document/cnicd_a095922.pdf |archive-date=26 January 2012 |access-date=7 August 2012 |publisher=US Navy}}</ref>

Diego Garcia was discovered by Portuguese sailors in 1512 and remained uninhabited until the French began using it as a [[leper colony]] and for [[Coconut#Production and cultivation|coconut plantations]] in the late 18th century. After the [[Napoleonic Wars]], the island was transferred to British control. It remained part of Mauritius until 1965, when it became part of the newly formed [[British Indian Ocean Territory]] (BIOT).

In 1966, Diego Garcia had a population of 924,<ref name="Islanders v AG 2003">{{cite BAILII|litigants=Chagos Islanders v Attorney General Her Majesty's British Indian Ocean Territory Commissioner|court=EWHC|division=QB|year=2003|num=2222|para=23|courtname=auto|date=9 October 2003}}</ref> mostly contract workers employed in [[Copra|coconut plantations]]. However, between 1968 and 1973, the Chagossian inhabitants were forcibly removed to make way for the military base. In 2019, the [[International Court of Justice]] issued a non-binding advisory opinion that the decolonisation of Mauritius had not been lawfully completed when it gained independence in 1968, and that the UK was "under an obligation to end its administration of the Chagos Archipelago as rapidly as possible". The [[United Nations General Assembly]] later voted overwhelmingly in favour of a resolution endorsing this opinion and calling on  the UK to end its administration, though the UK has dismissed the ruling as non-binding.<ref>{{Cite news |last=Boffey |first=Daniel |last2=reporter |first2=Daniel Boffey Chief |date=2026-01-20 |title=What are the Chagos Islands – and why is the UK returning them to Mauritius? |url=https://www.theguardian.com/world/2026/jan/20/what-are-chagos-islands-uk-mauritius-explainer |access-date=2026-01-22 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref><ref>{{Cite news |last=Bowcott |first=Owen |last2=Borger |first2=Julian |date=2019-05-22 |title=UK suffers crushing defeat in UN vote on Chagos Islands |url=https://www.theguardian.com/world/2019/may/22/uk-suffers-crushing-defeat-un-vote-chagos-islands |access-date=2026-01-22 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref>

Until the [[resettlement of Île du Coin]], Diego Garcia remained the only inhabited island of the BIOT, with a population of around 4,000 consisting predominantly of military personnel.<ref>{{Cite web |date=2026-01-21 |title=What is the Chagos Islands deal, and why has Trump accused the UK of 'stupidity'? |url=https://www.sbs.com.au/news/article/trump-chagos-islands-uk-deal-mauritius-explained/jvejjio2t |access-date=2026-01-22 |website=SBS News |language=en}}</ref> It is one of two critical U.S. [[bomber]] bases in the [[Indo-Pacific region]], alongside [[Andersen Air Force Base]] in [[Guam]].<ref name="thakkar">{{cite web |date=12 July 2021 |title=Chirayu Thakkar (12 Jul 2021) OVERCOMING THE DIEGO GARCIA STALEMATE |url=https://warontherocks.com/2021/07/overcoming-the-diego-garcia-stalemate/ |access-date=13 July 2021 |archive-date=13 July 2021 |archive-url=https://web.archive.org/web/20210713032927/https://warontherocks.com/2021/07/overcoming-the-diego-garcia-stalemate/ |url-status=live }}</ref> It is nicknamed the "Footprint of Freedom" by the [[U.S. Navy]]<ref>{{Cite web|title= About|url= https://cnrj.cnic.navy.mil/Installations/NSF-Diego-Garcia/About/|access-date= 2 November 2024|archive-date= 27 November 2024|archive-url= https://web.archive.org/web/20241127185737/https://cnrj.cnic.navy.mil/Installations/NSF-Diego-Garcia/About/|url-status= live}}</ref> due to its shape and strategic location in the Indian Ocean.<ref>{{Cite web |title=UK agrees to give sovereignty of the Chagos Islands to Mauritius |url=https://www.aljazeera.com/news/2024/10/3/uk-agrees-to-give-sovereignty-of-the-chagos-islands-to-mauritius |access-date=2024-10-04 |website=Al Jazeera |language=en}}</ref>

==History==

===Before European arrival===
[[File:DG Ariel Plantation.jpg|thumb|Coconut plantation, [[East Point, British Indian Ocean Territory|East Point]] (former main settlement)]]

No tangible evidence exists of people on Diego Garcia before the arrival of Europeans. There is speculation about visits during the [[Austronesia]]n diaspora around AD 700, as some say the old Maldivian name for the islands originated from [[Malagasy language|Malagasy]]. [[Arabs]], who reached [[Lakshadweep]] and [[Maldives]] around AD 900, may have visited the Chagos. Southern Maldivian [[oral tradition]] tells of occasional traders and fishermen marooned on, and later rescued from, Foalhavahi ({{langx|dv|ފޯޅަވަހި}}) Chagos.<ref>{{cite book |author=Xavier Romero Frías |author-link=Xavier Romero Frías |title=The Maldive Islanders, A Study of the Popular Culture of an Ancient Ocean Kingdom |location=Barcelona |publisher=Nova Ethnographia Indica |date=1999 |isbn=84-7254-801-5 |chapter=Chapter 1: A Seafaring Nation |page=19 }}</ref>

===European arrival===
The uninhabited islands were [[history of Portugal (1415–1578)#Chronology of the Portuguese discoveries|discovered]] by the Portuguese navigator, explorer, and diplomat [[Pedro Mascarenhas]] in 1512, first named as Dom Garcia, in honour of his patron, Dom [[Garcia de Noronha]]<ref>{{cite web |url=http://jmbd1945.blogspot.pt/2011_04_01_archive.html |title=Protugal Marítimo: Abril 2011 |first=Josmael |last=Bardour |work=jmbd1945.blogspot.pt |access-date=16 March 2014 |archive-date=16 March 2014 |archive-url=https://web.archive.org/web/20140316195930/http://jmbd1945.blogspot.pt/2011_04_01_archive.html |url-status=live }}</ref><ref>{{cite web |url=http://www.zianet.com/tedmorris/dg/dgtest.html |title=The Diego Garcia Test Question |work=zianet.com |access-date=16 March 2014|archive-date=23 October 2014 |archive-url=https://web.archive.org/web/20141023153117/http://www.zianet.com/tedmorris/dg/dgtest.html |url-status=live }}</ref>{{Better source needed |date=July 2023 }} when he was detached from the [[Portuguese India Armadas]]<ref>{{cite web|url=http://www.zianet.com/tedmorris/dg/realhistory.html|title=History of Diego Garcia Atoll, Indian Ocean|work=zianet.com|access-date=30 July 2010|archive-date=11 June 2011|archive-url=https://web.archive.org/web/20110611005507/http://www.zianet.com/tedmorris/dg/realhistory.html|url-status=live}}</ref>{{Better source needed|date=July 2023}} during his voyage of 1512–1513. Another Portuguese expedition with a Spanish explorer of Andalusian origin, [[Diego García de Moguer]],<ref>{{cite book|first=Edith|last= Porchat|title=Informações históricas sobre São Paulo no século de sua fundação|url=https://books.google.com/books?id=4FAezV2IKwUC&pg=PA61|year=1956|publisher=Editora Iluminuras Ltda|oclc=494596|page=61}}</ref> rediscovered the island in 1544 and named it after himself. Garcia de Moguer died the same year on the return trip to Portugal in the Indian Ocean, off the South African coast. The misnomer "Diego" could have been made unwittingly by the British ever since, as they copied the Portuguese maps. It is assumed{{by whom|date=December 2017}} that the island was named after one of its first two discoverers—the one by the name of Garcia, the other with name Diego. Also, a [[cacography]] of the saying {{lang|la|Deo Gracias}} (literally 'Thank God') is eligible for the attribution of the [[atoll]]. Although the [[Cantino planisphere]] (1504) and the [[Early world maps#Ruysch World Map (1507)|Ruysch map (1507)]] clearly delineate the Maldive Islands, giving them the same names, they do not show any islands to the south which can be identified as the Chagos archipelago.

[[File:Diego garcian.jpg|thumb|upright|An unnamed [[Chagossians|Chagossian]] photographed by a [[US National Geodetic Survey]] team in 1971]]
The [[Sebastian Cabot (explorer)|Sebastian Cabot]] map ([[Antwerp]] 1544) shows a number of islands to the south which may be the [[Mascarene Islands]]. The first map which identifies and names "''Los Chagos''" (in about the right position) is that of [[Pierre Desceliers]] ([[Dieppe maps#Existing Dieppe maps|Dieppe 1550]]), although Diego Garcia is not named. An island called "Don Garcia" appears on the {{lang|la|[[Theatrum Orbis Terrarum]]}} of [[Abraham Ortelius]] (Antwerp 1570), together with "Dos Compagnos", slightly to the north. It may be the case that "Don Garcia" was named after Garcia de Noronha, although no evidence exists to support this.{{Citation needed|date=August 2010}} The island is also labelled "Don Garcia" on [[Gerardus Mercator|Mercator]]'s ''[[Mercator 1569 world map|Nova et Aucta Orbis Terrae Descriptio ad Usum Navigatium Emendate]]'' (Duisburg 1569). However, on the {{lang|la|Vera Totius Expeditionis Nauticae Description}} of Jodocus Hondius (London 1589), "Don Garcia" mysteriously changes its name to "I. de Dio Gratia", while the "I. de Chagues" appears close by.

The first map to delineate the island under its present name, Diego Garcia, is the ''World Map'' of [[Edward Wright (mathematician)|Edward Wright]] (London 1599), possibly as a result of misreading ''Dio'' (or simply "D.") as Diego, and Gratia as Garcia. The {{lang|la|Nova Totius Terrarum Orbis Geographica}} of [[Hendrik Hondius II]] (Antwerp 1630) repeats Wright's use of the name, which is then proliferated on all subsequent Dutch maps of the period, and to the present day.

===Settlement of the island===
Diego Garcia and the rest of the Chagos islands were uninhabited until the late 18th century. In 1778, the French Governor of [[Mauritius]] granted Monsieur Dupuit de la Faye the island of Diego Garcia, and evidence exists of temporary French visits to collect coconuts and fish.<ref name="Edis_29">[[#Edis|Edis (2004)]], p. 29.</ref> Several Frenchmen living in "a dozen huts" abandoned Diego Garcia when the British [[East India Company]] attempted to establish a settlement there in April 1786.<ref name="Edis_29"/> The supplies of the 275 settlers were overwhelmed by 250 survivors of the wreck of the British East Indian Ship  ''Atlas'' in May, and the colony failed in October.<ref name="Edis_32">[[#Edis|Edis (2004)]], p. 32.</ref> Following the departure of the British, the French colony of Mauritius began marooning [[lepers]] on the island,<ref name="Edis_32"/> and in 1793, the French established a [[coconut]] plantation using [[slave labour]], which exported cordage made from coir (coconut fibre), and [[sea cucumber]]s as a far-eastern delicacy.<ref>[[#Edis|Edis (2004)]], p. 33.</ref>

Diego Garcia became a colony of the UK after the [[Napoleonic Wars]] as part of the [[Treaty of Paris (1814)]], and from 1814 to 1965 it was administered from Mauritius;<ref name="Edis 2004, p. 80"/> the main plantations were at East Point, the main settlement, Minni Minni, {{convert|4.5|km|mi|abbr=in}} north of East Point, and Pointe Marianne, on the western rim, all on the lagoon side of the atoll. The workers lived at each and at villages scattered around the atoll.

From 1881 until 1888, the atoll hosted two [[Fuelling station|coaling stations]] for [[steamships]] crossing the Indian Ocean.<ref name="Stoddart_209_218">D. R. Stoddart (1971): "Settlement and development of Diego Garcia". In: [[#Stoddart|Stoddart & Taylor (1971)]], pp. 209–218.</ref>

In 1882, the French-financed, Mauritian-based {{lang|fr|Société Huilière de Diego et de Peros}} (the 'Oilmaking Company of Diego and Peros'), consolidated all the plantations in the Chagos under its control.<ref name="Stoddart_209_218"/>

===20th century===
[[File:Barochois Maurice, Diego Garcia.jpg|thumb|[[Barachois]] Maurice, Diego Garcia]]
[[File:Consolidated PBY Catalina wreck on Diego Garcia 1982.jpg|thumb|Catalina wreck on the beach]]

In 1914, the island was visited by the German light cruiser {{SMS|Emden}} halfway through its commerce-raiding cruise during the early months of [[World War&nbsp;I]].<ref>{{cite book|url=https://books.google.com/books?id=tPUMAAAAYAAJ |title=Helmuth von Mucke 'The Emden' |year=1916 |page= 130 |last1=Mücke |first1=Hellmuth von }}</ref>

In 1942, the British opened RAF Station Diego Garcia and established an advanced flying boat unit at the East Point Plantation, staffed and equipped by [[No. 205 Squadron RAF|No. 205]] and [[No. 240 Squadron RAF|No. 240 Squadron]]s, then stationed on Ceylon. Both [[Consolidated PBY Catalina|Catalina]] and [[Short Sunderland|Sunderland]] aircraft were flown during the course of [[World War&nbsp;II]] in search of Japanese and German submarines and surface raiders. At Cannon Point,<ref name="youtube.com">{{cite web|url=https://www.youtube.com/watch?v=s1211xF65ac| archive-url=https://web.archive.org/web/20111128015132/http://www.youtube.com/watch?v=s1211xF65ac| archive-date=28 November 2011 | url-status=dead|title=Cannon Point, Diego Garcia|last=subiepowa|date=28 April 2007|via=YouTube}}</ref> two {{convert|6|in|mm|adj=on}} naval guns were installed by a [[Royal Marines]] detachment. In February 1942, the mission was to protect the small Royal Navy base and Royal Air Force station located on the island from Japanese attack.<ref name="youtube.com"/> Operation of the guns was later taken over by Mauritian and Indian Coastal Artillery troops.<ref>[[#Edis|Edis (2004)]], p. 73.</ref> Following the conclusion of hostilities, the station was closed on 30 April 1946.<ref>[[#Edis|Edis (2004)]], p. 70.</ref>

In 1962, the Chagos Agalega Company of the British colony of Seychelles purchased the Société Huilière de Diego et Peros and moved company headquarters to Seychelles.<ref name="Edis_82">[[#Edis|Edis (2004)]], p. 82.</ref>

In the early 1960s, the UK was [[East of Suez#20th century|withdrawing its military presence]] from the Indian Ocean, not including the airfield at [[RAF Gan]] to the north of Diego Garcia in the Maldives (which remained open until 1976), and agreed to permit the United States to establish a naval communication station on one of its island territories there. The United States requested an unpopulated island belonging to the UK to avoid political difficulties with newly independent countries, and ultimately the UK and United States agreed that Diego Garcia was a suitable location.<ref name="Sand_3">[[#Sand|Sand (2009)]], p. 3.</ref>

===Purchase by the United Kingdom===
[[File:Ted Morris on Diego Garcia.jpg|thumb|upright|An [[unpaved road]] in Diego Garcia in the eastern restricted zone, home to the former plantations]]

To accomplish the UK–US mutual defence strategy, in November 1965, the UK purchased the [[Chagos Archipelago]], which includes Diego Garcia, from the then self-governing colony of Mauritius for £3 million to create the [[British Indian Ocean Territory]] (BIOT), with the intent of ultimately closing the plantations to provide the uninhabited British territory from which the United States would conduct its military activities in the region.<ref name="Sand_3"/>

In April 1966, the British government bought the entire assets of the Chagos Agalega Company in the BIOT for £600,000 and administered them as a government enterprise and immediately leased the plantations back to Chagos Agalega while awaiting United States funding of the proposed facilities, with an interim objective of paying for the administrative expenses of the new territory.<ref name="Edis_82"/> However, the plantations, both under their previous private ownership and under government administration, proved consistently unprofitable due to the introduction of new oils and lubricants in the international marketplace, and the establishment of vast coconut plantations in the East Indies and the Philippines and the company terminated the lease at the end of 1967.<ref>{{cite BAILII|litigants=Chagos Islanders v Attorney General and Her Majesty's British Indian Ocean Territory Commissioner |year=2003 |num=2222 |court=EWHC |division=QB |date=9 October 2003}}</ref>

On 30 December 1966, the United States and the UK executed an agreement through an Exchange of Notes which permitted the United States to use the BIOT for defence purposes for 50 years until December 2016, followed by a 20-year extension (to 2036) as long as neither party gave notice of termination in a two-year window (December 2014 – December 2016) and the UK may decide on what additional terms to extend the agreement.<ref>"[https://publications.parliament.uk/pa/cm201415/cmselect/cmfaff/377/37702.htm Report: The use of Diego Garcia by the United States] {{Webarchive|url=https://web.archive.org/web/20171201043141/https://publications.parliament.uk/pa/cm201415/cmselect/cmfaff/377/37702.htm |date=1 December 2017 }}". UK Parliament, September 2014</ref> No monetary payment was made from the United States to the UK as part of this agreement or any subsequent amendment. Rather, the United Kingdom received a US$14-million discount from the United States on the acquisition of submarine-launched [[Polaris missiles]] per a now-declassified addendum to the 1966 agreement.<ref>[[#Sand|Sand (2009)]], pp. 6–8.</ref>

===Arrival of the U.S. Navy===
To the United States, Diego Garcia was a prime territory for setting up a foreign military base. According to Stuart Barber—a civilian working for the US Navy at [[the Pentagon]]—Diego Garcia was located far away from any potential threats, it was low in a native population and it was an island that was not sought after by other countries as it lacked economic interest. To Barber, Diego Garcia and other acquired islands would play a key role in maintaining US dominance. Here Barber designed the strategic island concept, where the US would obtain as many less populated islands as possible for military purposes. According to Barber, this was the only way to ensure security for a foreign base. Diego Garcia is often referred to as "Fantasy Island" for its seclusion.

[[File:Seychelles Governor inspection 1972.jpg|thumb|right|upright=0.9|[[Bruce Greatbatch|Sir Bruce Greatbatch]], [[Governor of the Seychelles]], oversaw the [[depopulation of Chagossians from the Chagos Archipelago]].]]
The key component in obtaining Diego Garcia was the perceived lack of a native population on the island. Uninhabited until the late 18th century, Diego Garcia had no indigenous population. Its only inhabitants were European overseers who managed the coconut plantations for their absentee landowners and contract workers mostly of African, Indian, and Malay ancestry, known as [[Chagossians]], who had lived and worked on the plantations for several generations. Prior to setting up a military base, the United States government was informed by the British government—which owned the island—that Diego Garcia had a population of hundreds. The eventual number of Chagossians numbered around 1,000.<ref name="Health_and_Mortality_papers">{{cite book |url=http://www.zianet.com/tedmorris/dg/chagosmortalityreport.pdf |archive-url=https://web.archive.org/web/20071024211628/http://www.zianet.com/tedmorris/dg/chagosmortalityreport.pdf |archive-date=24 October 2007 |url-status=live |publisher=[[Foreign and Commonwealth Office]] |title=Health & Mortality in the Chagos Islands |series=Research and Analytical Papers |author=African Research Group |year=2000 |access-date=27 September 2011}}</ref>

The Chagossians were removed from the island before the base was constructed. In 1968, the first tactics were implemented to decrease the population of Diego Garcia. Those who left the island—either for vacation or medical purposes—were not allowed to return, and those who stayed could obtain only restricted food and medical supplies. This tactic was in hope that those that stayed would leave "willingly".<ref name="WashingtonPost-2007-01-01">{{cite news | url = https://www.washingtonpost.com/wp-dyn/content/article/2007/01/01/AR2007010100698.html | title = Island of Injustice | author = David Vine | newspaper = [[The Washington Post]] | archive-date = 10 August 2017 | access-date = 27 August 2017 | archive-url = https://web.archive.org/web/20170810112003/http://www.washingtonpost.com/wp-dyn/content/article/2007/01/01/AR2007010100698.html | url-status = live }}</ref> One of the tactics used was ordering all Chagossian dogs to be killed.<ref name="murder">{{cite news |url=http://www.hartford-hwp.com/archives/27b/036.html |title=Diego Garcia—How the Brits deported a nation |date=22 October 2004 |newspaper=Z Magazine |access-date=3 October 2024 |archive-date=7 October 2024 |archive-url=https://web.archive.org/web/20241007091935/http://www.hartford-hwp.com/archives/27b/036.html |url-status=live }}</ref>

In March 1971, United States Naval [[Seabee|construction battalions]] arrived on Diego Garcia to begin the construction of the communications station and an airfield.<ref>{{cite web |first=Ted |last=Morris |url=http://www.zianet.com/tedmorris/dg/71.html |title=Personal Accounts of Landing on Diego Garcia, 1971 |publisher=Zianet.com |access-date=21 June 2012 |archive-date=14 March 2011 |archive-url=https://web.archive.org/web/20110314140054/http://www.zianet.com/tedmorris/dg/71.html |url-status=live }}</ref>{{Better source needed|date=July 2023}} To satisfy the terms of an agreement between the UK and the United States for an uninhabited island, the plantation on Diego Garcia was closed in October of that year.<ref name="Sand_24">[[#Sand|Sand (2009)]], p. 24.</ref> The plantation workers and their families were relocated to the plantations on Peros Banhos and Salomon atolls to the northwest. The by-then-independent Mauritian government refused to accept the islanders without payment, and in 1974, the UK gave the Mauritian government an additional £650,000 to resettle the islanders.<ref name="Sand_25">[[#Sand|Sand (2009)]], p. 25.</ref> Those who still remained on the island of Diego Garcia between 1971 and 1973 were forced onto cargo ships that were heading to Mauritius and the Seychelles.

By 1973, construction of the Naval Communications Station was complete.<ref>[[#Edis|Edis (2004)]], p. 88.</ref> In the early 1970s, setbacks to United States military capabilities in the region including the [[fall of Saigon]], victory of the [[Khmer Rouge]] in Cambodia, the closure of the [[Peshawar Air Station]] listening post in [[Pakistan]] and [[Kagnew Station]] in Eritrea, the [[Mayaguez incident|''Mayaguez'' incident]], and the build-up of Soviet naval presence in [[Aden]] and a Soviet airbase at Berbera, [[Somalia]], caused the United States to request, and the UK to approve, permission to build a fleet anchorage and enlarged airfield on Diego Garcia,<ref name="Edis_90">[[#Edis|Edis (2004)]], p. 90.</ref> and the [[Seabee]]s doubled the number of workers constructing these facilities.<ref name="Edis_90"/>

[[File:The O Club on Diego Garcia.jpg|thumb|This 1982 photo shows an [[unpaved road]] made of crushed coral common throughout the island and the officers' dining area at the Diego Garcia Naval Support Facility.]]

Following the fall of the [[Shah of Iran]] and the [[Iran Hostage Crisis]] in 1979–1980, the West became concerned with ensuring the flow of oil from the [[Persian Gulf]] through the [[Strait of Hormuz]], and the United States received permission for a $400-million expansion of the military facilities on Diego Garcia consisting of two parallel {{convert|12000|ft|m|adj=mid|-long}} runways, expansive parking aprons for heavy bombers, 20 new anchorages in the lagoon, a deep-water pier, port facilities for the largest naval vessels in the U.S. and British fleets, aircraft hangars, maintenance buildings and an air terminal, a {{convert|1340000|oilbbl}} fuel storage area, and [[billet]]ing and messing facilities for thousands of sailors and support personnel.<ref name="Edis_90"/> The closure of the U.S. bases in the [[Philippines]] in the early 1990s brought many workers from [[U.S. Naval Base Subic Bay|Subic Bay]] and [[Clark Air Base]] to Diego Garcia.<ref>{{cite web | url=https://www.andersen.af.mil/News/Commentaries/Display/Article/416777/diego-garcias-master-budget-analyst-resource-advisor-recognized/ | title=Diego Garcia's master budget analyst, resource advisor recognized | date=8 May 2013 | access-date=11 March 2023 | archive-date=11 March 2023 | archive-url=https://web.archive.org/web/20230311011516/https://www.andersen.af.mil/News/Commentaries/Display/Article/416777/diego-garcias-master-budget-analyst-resource-advisor-recognized/ | url-status=live }}</ref>

===21st century===
On 23 June 2017, the [[United Nations General Assembly]] (UNGA) voted in favour of referring the territorial dispute between Mauritius and the UK to the [[International Court of Justice]] (ICJ) in order to clarify the legal status of the Chagos Islands archipelago in the Indian Ocean. The motion was approved by a majority vote with 94 voting for and 15 against.<ref>{{cite news|last1=Sengupta|first1=Somini|title=U.N. Asks International Court to Weigh in on Britain-Mauritius Dispute|url=https://www.nytimes.com/2017/06/22/world/europe/uk-mauritius-chagos-islands.html|work=The New York Times|date=22 June 2017|archive-date=27 December 2019|access-date=23 June 2017|archive-url=https://web.archive.org/web/20191227214438/https://www.nytimes.com/2017/06/22/world/europe/uk-mauritius-chagos-islands.html|url-status=live}}</ref><ref>{{cite news|title=Chagos legal status sent to international court by UN|url=https://www.bbc.com/news/uk-40376673|access-date=23 June 2017|work=BBC News|date=22 June 2017|archive-date=3 July 2021|archive-url=https://web.archive.org/web/20210703075109/https://www.bbc.com/news/uk-40376673|url-status=live}}</ref>

In February 2019, the ICJ in [[The Hague]] ruled that the United Kingdom must transfer the islands to Mauritius as they were not legally separated from the latter in 1965. The UK Foreign Office said the ruling is not legally binding.<ref name="bbc.com">{{cite web |title=Chagos Islands dispute: UK obliged to end control – UN |url=https://www.bbc.com/news/uk-47358602 |work=BBC News |date=25 February 2019 |access-date=25 February 2019 |archive-date=26 January 2021 |archive-url=https://web.archive.org/web/20210126230026/https://www.bbc.com/news/uk-47358602 |url-status=live }}</ref>  In May 2019, the United Nations General Assembly affirmed the decision of the International Court of Justice and demanded that the United Kingdom withdraw its colonial administration from the Islands and cooperate with Mauritius to facilitate the resettlement of Mauritian nationals in the archipelago.<ref>{{cite web |title=UK suffers crushing defeat in UN vote on Chagos Islands |url=https://www.theguardian.com/world/2019/may/22/uk-suffers-crushing-defeat-un-vote-chagos-islands |work=The Guardian |date=23 May 2019 |access-date=6 June 2019 |archive-date=23 May 2019 |archive-url=https://web.archive.org/web/20190523022954/https://www.theguardian.com/world/2019/may/22/uk-suffers-crushing-defeat-un-vote-chagos-islands |url-status=live }}</ref><ref>{{cite web |title=Resolution adopted by the General Assembly on 22 May 2019 |url=https://www.un.org/en/ga/search/view_doc.asp?symbol=A/RES/73/295 |work=UN General Assembly |date=22 May 2019 |access-date=6 June 2019 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308160804/https://www.un.org/en/ga/search/view_doc.asp?symbol=A/RES/73/295 |url-status=live }}</ref>  In a written statement, the U.S. government said that neither the Americans nor the British have any plans to discontinue use of the military base on Diego Garcia. The statement said in a footnote: "In 2016, there were discussions between the United Kingdom and the United States concerning the continuing importance of the joint base. Neither party gave notice to terminate and the agreement remains in force until 2036".<ref>{{cite web |url= https://www.stripes.com/news/un-ruling-raises-questions-about-future-of-us-mission-in-diego-garcia-1.571709 |title= UN ruling raises questions about future of US mission in Diego Garcia |date= 7 March 2019 |first= Joshua |last= Karsten |publisher= Stars and Stripes |access-date= 16 June 2019 |archive-date= 16 June 2019 |archive-url= https://web.archive.org/web/20190616221338/https://www.stripes.com/news/un-ruling-raises-questions-about-future-of-us-mission-in-diego-garcia-1.571709 |url-status= live }}</ref><ref name= thakkar />

In June 2020, a Mauritian official offered to allow the United States to retain its military base on the island if Mauritius succeeded in regaining sovereignty over the Chagos archipelago.<ref>{{cite web |url=https://seapowermagazine.org/navy-base-in-diego-garcia-welcome-to-stay-after-transfer-of-sovereignty-official-says/ |title=Navy Base in Diego Garcia Welcome to Stay After Transfer of Sovereignty, Official Says |last=Burgess |first=Richard R. |date=24 June 2020 |website=Seapower Magazine |publisher=[[Navy League of the United States]] |access-date=19 June 2020 |quote=The U.S. Navy base in Diego Garcia, an outpost in the Chagos archipelago in the Indian Ocean, would be welcome to remain if Mauritius succeeds in its sovereignty claim over the archipelago, currently known as the British Indian Ocean Territories (BIOT), a Mauritian official said. |archive-date=30 July 2020 |archive-url=https://web.archive.org/web/20200730214555/https://seapowermagazine.org/navy-base-in-diego-garcia-welcome-to-stay-after-transfer-of-sovereignty-official-says/ |url-status=live }}</ref>

===Chagos Marine Protected Area===
On 1 April 2010, the [[Chagos Marine Protected Area]] (MPA) was declared to cover the waters around the Chagos Archipelago. However, Mauritius objected, stating this was contrary to its legal rights, and on 18 March 2015, in light of the ''[[Mauritius v. United Kingdom]]'' case, the [[Permanent Court of Arbitration]] ruled that the Chagos Marine Protected Area was illegal under the [[United Nations Convention on the Law of the Sea]] as Mauritius had legally binding rights to fish in the waters surrounding the Chagos Archipelago, to an eventual return of the Chagos Archipelago, and to the preservation of any minerals or oil discovered in or near the Chagos Archipelago prior to its return.<ref name="guardian-20150319">{{cite news |url=https://www.theguardian.com/world/2015/mar/19/un-ruling-raises-hope-of-return-for-exiled-chagos-islanders |title=UN ruling raises hope of return for exiled Chagos islanders |first=Owen |last=Bowcott |author2=Sam Jones |newspaper=The Guardian |date=19 March 2015 |access-date=29 March 2015 |archive-date=4 July 2015 |archive-url=https://web.archive.org/web/20150704214813/http://www.theguardian.com/world/2015/mar/19/un-ruling-raises-hope-of-return-for-exiled-chagos-islanders |url-status=live }}</ref><ref name="cga-pressrelease">{{cite web|url=http://www.pca-cpa.org/showfile.asp?fil_id=2901 |title=Chagos Marine Protected Area Arbitration (Mauritius v. United Kingdom) (Press Release and Summary of Award) |publisher=Permanent Court of Arbitration |date=19 March 2015 |access-date=29 March 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150402064110/http://www.pca-cpa.org/showfile.asp?fil_id=2901 |archive-date= 2 April 2015 }}</ref>

=== Transfer to Mauritius ===
On 3 October 2024, the UK prime minister [[Keir Starmer]] announced in a statement with the Mauritian prime minister [[Pravind Jugnauth]] that the UK will hand over the Chagos islands to Mauritius. The joint base on the island will stay, with the UK initially taking a 99-year lease of the base from Mauritius. Mauritius will be allowed to begin resettlement on the Chagos Archipelago, but not on Diego Garcia due to the sensitive nature of the base. U.S. president [[Joe Biden]] welcomed the agreement, saying that it was a "clear demonstration that through diplomacy and partnership, countries can overcome long-standing historical challenges to reach peaceful and mutually beneficial outcomes".<ref name="Harding-2024">{{Cite web |last=Harding |first=Andrew |date=2024-10-03 |title=UK will give sovereignty of Chagos Islands to Mauritius |url=https://www.bbc.co.uk/news/articles/c98ynejg4l5o |access-date=2024-10-03 |website=[[BBC News]] |language=en-GB |archive-date=3 October 2024 |archive-url=https://web.archive.org/web/20241003225136/https://www.bbc.co.uk/news/articles/c98ynejg4l5o |url-status=live }}</ref> The deal was put on hold following the [[2024 United States presidential election]] to allow consideration from the [[Second cabinet of Donald Trump|incoming Trump administration]].<ref>{{Cite news |last1=Crerar |first1=Pippa |last2=Walker |first2=Peter |date=2025-01-15 |title=UK stalls Chagos Islands deal until Trump administration can 'consider detail' |url=https://www.theguardian.com/world/2025/jan/15/uk-chagos-islands-handover-mauritius-donald-trump-diego-garcia |access-date=2025-01-17 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> On 1 April 2025, the new administration approved letting treaty negotiations continue.<ref name="The Guardian April 2025">{{cite web | last=Courea | first=Eleni | title=Donald Trump signs off UK's handover of Chagos Islands to Mauritius | website=the Guardian | date=April 1, 2025 | url=https://www.theguardian.com/world/2025/apr/01/donald-trump-signs-off-uks-handover-of-chagos-islands-to-mauritius | access-date=May 6, 2025}}</ref>

On 22 May 2025, Starmer signed a formal agreement on the transfer of sovereignty of the Chagos Islands to Mauritius.<ref>{{Cite news |date=2025-05-23 |title=UK hands over Chagos Islands to Mauritius in landmark sovereignty deal |url=https://timesofindia.indiatimes.com/world/uk/uk-hands-over-chagos-islands-to-mauritius-in-landmark-sovereignty-deal/articleshow/121343441.cms |access-date=2025-05-23 |work=The Times of India |issn=0971-8257}}</ref> Under the terms of the deal, the strategic atoll of Diego Garcia and its surrounding {{convert|24|mi|km|-1|adj=on}} buffer zone are immediately leased back to the UK. This arrangement permits the continued operation of the joint British–American base on the island for the next 99 years, with an additional 40-year extension and a subsequent right of first refusal.<ref>{{Cite web |title=UK Hands Over Control of Chagos Islands to Mauritius |url=https://maritime-executive.com/article/uk-hands-sovereignty-over-diego-garcia-and-chagos-islands-to-mauritius |access-date=2025-05-23 |website=The Maritime Executive |language=en}}</ref>

In June 2025, British Conservatives asserted that the restitution agreement will cost the British taxpayer more than the agreement to return the Chagos Archipelago to Mauritius was expected to cost.<ref>{{cite web |url=https://www.telegraph.co.uk/news/2025/06/14/starmers-chagos-surrender-will-cost-5bn-more-than-feared/ |title=Starmer's Chagos surrender 'will cost £5bn more than feared' |work=telegraph.co.uk |date=14 June 2025 |access-date=14 June 2025}}</ref>

In January 2026, the Trump administration reversed their previous approval of the transfer with a post by Donald Trump on [[Truth Social]] reading in part: "Shockingly, our ‘brilliant’ NATO Ally, the United Kingdom, is currently planning to give away the Island of Diego Garcia, the site of a vital U.S. Military Base, to Mauritius, and to do so FOR NO REASON WHATSOEVER...  The UK giving away extremely important land is an act of GREAT STUPIDITY, and is another in a very long line of National Security reasons why Greenland has to be acquired." The criticism of the transfer appeared to be a part of the ongoing [[Greenland crisis]].<ref>{{Cite news |last=Ray |first=Siladitya |title=Trump Shares Macron's Private Text Questioning His Greenland Stance |url=https://www.forbes.com/sites/siladityaray/2026/01/20/trump-shares-private-texts-sent-by-macron-and-nato-secretary-general-on-greenland/ |access-date=2026-01-20 |work=Forbes |language=en}}</ref>

In February 2026, UK [[Secretary of State for Defence]], [[John Healey]], was accused by the [[Conservative Party (UK)|Conservatives]] of [[Misleading of parliament|misleading parliament]], by claiming in May 2025, that if the UK did not cede the [[British Indian Ocean Territory]] ([[Chagos Archipelago]]) to [[Mauritius]], it could face losing legal rulings "within weeks", and "within just a few years" the base at Diego Garcia "would become inoperable".<ref name="chagos">{{cite web |author1=Genevieve Holl-Allen |title=Defence Secretary ‘misled Parliament over Chagos deal’ |url=https://www.telegraph.co.uk/politics/2026/02/20/chagos-islands-john-healey-accused-of-misleading-parliament/ |website=[[The Daily Telegraph]] |access-date=21 February 2026|url-access=subscription }}</ref> Healy claimed that "the most proximate, and the most potentially serious" threat was the [[International Tribunal for the Law of the Sea]] (ITLOS), however under [[United Nations Convention on the Law of the Sea#Article_298|Article 298]] of the [[United Nations Convention on the Law of the Sea]] (UNCLOS) there is an exemption for "disputes concerning military activities, including military activities by government".<ref name="chagos"/>

=== Alleged 2026 Iranian attack ===
In March 2026, Iran allegedly{{According to whom|date=March 2026}} fired two ballistic missiles at the Diego Garcia military base as part of the [[2026 Iran war]]. One failed in flight and the other was shot down by a U.S. warship with an [[RIM-161 Standard Missile 3|SM-3]] missile.<ref>{{Cite web |title=Iran Targeted Diego Garcia Base With Ballistic Missiles |url=https://www.wsj.com/livecoverage/iran-us-israel-war-updates-2026/card/iran-targeted-diego-garcia-base-with-ballistic-missiles-rb7MdZW1CfwRTauDYHOt |access-date=2026-03-21 |website=The Wall Street Journal |language=en-US}}</ref> Iran later denied claims that it launched missiles towards Diego Garcia, saying that it was an "Israeli false flag” attack.<ref>{{Cite web |title=‘False flag attack’: Iran denies claims it fired missiles at Diego Garcia |url=https://www.aljazeera.com/news/2026/3/23/iran-denies-targeting-us-uk-diego-garcia-airbase-claims-false-flag-attack |access-date=2026-03-23 |website=Al Jazeera |language=en-US}}</ref> [[Mark Rutte]], the Secretary General of NATO during an interview with CBS News said that [[NATO]] cannot confirm that Iran has fired missiles towards the remote strategic military base in the Indian Ocean.<ref>{{Cite web |date=2026-03-22 |title=Transcript: NATO Secretary General Mark Rutte on "Face the Nation with Margaret Brennan," March 22, 2026 - CBS News |url=https://www.cbsnews.com/news/mark-rutte-nato-secretary-general-face-the-nation-transcript-03-22-2026/ |access-date=2026-03-25 |website=www.cbsnews.com |language=en-US}}</ref><ref>{{Cite web |title=Nato 'cannot confirm' Iran behind attack on UK-US base after Iranian denial |url=https://www.middleeasteye.net/news/nato-cannot-confirm-iran-behind-attack-uk-us-base-after-iranian-denial |access-date=2026-03-25 |website=Middle East Eye |language=en}}</ref>

==Inhabitants==
Diego Garcia had no permanent inhabitants when discovered by the Spanish explorer Diego García de Moguer in the 16th century, then in the service of Portugal, and this remained the case until it was settled as a French colony in 1793.<ref name="Stoddart_209_218"/>

===French settlement===
{{main|Chagossians}}

Most inhabitants of Diego Garcia through the period 1793–1971 were plantation workers, but also included Franco-Mauritian managers, Indo-Mauritian administrators, Mauritian and Seychellois contract employees, and in the late 19th century, Chinese and Somali employees.

A distinct Creole culture called the [[Îlois]], which means "islanders" in [[French-based creole languages|French Creole]], evolved from these workers. The Îlois, now called Chagos Islanders or Chagossians since the late-1990s, were descended primarily from [[slaves]] brought to the island from [[Madagascar]] by the French between 1793 and 1810, and [[Malay race|Malay]] slaves from the slave market on [[Nias Island|Pulo Nyas]], an island off the northwest coast of [[Sumatra]], from around 1820 until the slave trade ended following the [[Slavery Abolition Act 1833]].<ref name="reefnewmedia.co.uk">{{cite web|url=http://www.reefnewmedia.co.uk/cmt_chagos/uploads/PDF/Newsletters/ChagosNews14.pdf |title=Slavery in the Chagos Archipelago |access-date=21 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120119043547/http://www.reefnewmedia.co.uk/cmt_chagos/uploads/PDF/Newsletters/ChagosNews14.pdf |archive-date=19 January 2012 }}</ref> The Îlois also evolved a French-based [[Mauritian Creole|Creole dialect]] now called [[Chagossian Creole]].

Throughout their recorded history, the plantations of the Chagos Archipelago had a population of approximately 1,000 individuals, about two-thirds of whom lived on Diego Garcia. A peak population of 1,142 on all islands was recorded in 1953.<ref name="Health_and_Mortality_papers"/>

The primary industry throughout the island's colonial period consisted of coconut [[plantations]] producing [[copra]] and/or [[coconut oil]],<ref name="Stoddart_209_218"/> until closure of the plantations and forced relocation of the inhabitants in October 1971. For a brief period in the 1880s, it served as a [[coaling station]] for steamships transiting the Indian Ocean from the [[Suez Canal]] to Australia.<ref>[[#Edis|Edis (2004)]], pp. 49–54.</ref>

===Expulsion of 1971===
{{main|Expulsion of the Chagossians}}

All the inhabitants of Diego Garcia were forcibly resettled to other islands in the Chagos Archipelago, Mauritius or Seychelles by 1971 to satisfy the requirements of a UK/United States Exchange of Notes signed in 1966 to depopulate the island when the United States constructed a base upon it.<ref>{{cite web|url=http://www.hmcourts-service.gov.uk/judgmentsfiles/j1970/chagos.htm |title=England and Wales High Court of Justice, Queens Bench Division Appendix, Paragraph 396 |publisher=Hmcourts-service.gov.uk |date=1 April 2011 |access-date=21 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20100604072841/http://www.hmcourts-service.gov.uk/judgmentsfiles/j1970/chagos.htm |archive-date=4 June 2010 }}</ref> No current agreement exists on how many of the evacuees met the criteria to be an Îlois, and thus be an indigenous person at the time of their removal, but the UK and Mauritian governments agreed in 1972 that 426 families,<ref>{{cite web|url=http://www.hmcourts-service.gov.uk/judgmentsfiles/j1970/chagos.htm |title=England and Wales High Court of Justice, Queens Bench Division Appendix, Paragraph 417 |publisher=Hmcourts-service.gov.uk |date=1 April 2011 |access-date=21 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20100604072841/http://www.hmcourts-service.gov.uk/judgmentsfiles/j1970/chagos.htm |archive-date=4 June 2010 }}</ref> numbering 1,151 individuals,<ref name="Sand_25"/> were due compensation payments as exiled Îlois. The total number of people certified as Îlois by the Mauritian Government's Îlois Trust Fund Board in 1982 was 1,579.<ref>{{cite web |url=http://www.uniset.ca/naty/2003EWHC2222.htm |title=Paragraph 629 |publisher=Uniset.ca |access-date=21 June 2012 |archive-date=16 July 2016 |archive-url=https://web.archive.org/web/20160716081343/http://www.uniset.ca/naty/2003EWHC2222.htm |url-status=live }}</ref>

Fifteen years after the last expulsion, the Chagossians received compensation from the British, totalling $6,000 per person; some Chagossians received nothing. The British expulsion action remains in litigation {{As of|2016|lc=y}}.<ref>{{cite web|url=http://www.eeas.europa.eu/british_indian_ocean_territory/index_en.htm |title=European Union – EEAS (European External Action Service) |work=europa.eu |url-status=dead |archive-url=https://web.archive.org/web/20101225061830/http://eeas.europa.eu/british_indian_ocean_territory/index_en.htm |archive-date=25 December 2010 }}</ref><ref>{{cite news |url=https://www.theguardian.com/world/2010/sep/27/chagos-islands-maldives-seabed-claim?intcmp=239 |title=Chagos Islands exiles amazed by speed of Foreign Office's opposition to seabed claim by Maldives |first=Owen|last= Bowcott |date=27 September 2010 |newspaper=The Guardian |access-date=27 September 2011}}</ref> Today, Chagossians remain highly impoverished and are living as "marginalised" outsiders on the island of Mauritius and the Seychelles.<ref>{{Cite web|title=Chagossians-the original inhabitants of Diego Garcia face U.S. government in the court|url=http://www.culturalsurvival.org/news/chagossians-original-inhabitants-diego-garcia-face-us-government-court|access-date=2 February 2022|website=www.culturalsurvival.org|date=8 February 2002|language=en|archive-date=28 March 2022|archive-url=https://web.archive.org/web/20220328163052/https://www.culturalsurvival.org/news/chagossians-original-inhabitants-diego-garcia-face-us-government-court|url-status=live}}</ref>

===After 1971===
Between 1971 and 2001, the only residents on Diego Garcia were British and American military personnel and civilian employees of those countries. These included contract employees from the Philippines and Mauritius, including some [[Îlois]].<ref>{{cite web| first=Ted A.|last= Morris Jr. |url=http://www.zianet.com/tedmorris/dg/bancoult-and-tigar-vs-USA-02.html |title=See email claims from John Bridiane |publisher=Zianet.com |access-date=21 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120924081644/http://www.zianet.com/tedmorris/dg/bancoult-and-tigar-vs-USA-02.html |archive-date=24 September 2012 }}</ref>{{Better source needed|date=July 2023}} During combat operations from the atoll [[War in Afghanistan (2001–2021)|against Afghanistan]] (2001–2006) and [[Iraq War|Iraq]] (2003–2006), a number of allied militaries were based on the island including Australian,<ref>{{cite web |url=http://gc.nautilus.org/Nautilus/australia/afghanistan/adf-in-afghanistan-history |title=ADF in Afghanistan – history — Global Collaborative |website=gc.nautilus.org |access-date=13 January 2022 |archive-url=https://web.archive.org/web/20090106010223/http://gc.nautilus.org/Nautilus/australia/afghanistan/adf-in-afghanistan-history |archive-date=6 January 2009 |url-status=dead}}</ref> Japanese, and the Republic of Korea.{{citation needed|date=June 2023}} According to David Vine, "Today, at any given time, 3,000 to 5,000 US troops and civilian support staff live on the island."<ref>David Vine, (2009) ''Island of Shame: The Secret History of the U.S. Military Base on Diego Garcia'', Princeton: Princeton University Press. p. 6.</ref> The inhabitants today do not rely on the island and the surrounding waters for sustenance. Although some recreational fishing for consumption is permitted, all other food is shipped in by sea or air.<ref>[[#Sheppard Spalding|Sheppard & Spalding (2003)]], p. 28.</ref>

In 2004, U.S. Navy recruitment literature described Diego Garcia as being one of the world's best-kept secrets, boasting great recreational facilities, exquisite natural beauty, and outstanding living conditions.<ref>[http://www.parliament.uk/edm/2003-04/1680 Early day motion 1680] {{Webarchive|url=https://web.archive.org/web/20160605063326/http://www.parliament.uk/edm/2003-04/1680 |date=5 June 2016 }} UK Parliament, 16 September 2004</ref>

Since October 2021, there have been [[British Indian Ocean Territory#Marooned asylum seekers|asylum seekers on Diego Garcia]].<ref>{{Cite web |last=Cuddy |first=Alice |date=29 September 2024 |title=What I found on the secretive tropical island they don't want you to see |url=https://www.bbc.com/news/articles/ckdg7jjlx2go |access-date=2024-10-04 |website=[[BBC News]] |language=en-GB |archive-date=30 September 2024 |archive-url=https://web.archive.org/web/20240930122242/https://www.bbc.com/news/articles/ckdg7jjlx2go |url-status=live }}</ref>

==Governance==

Originally colonised by the French, Diego Garcia was ceded, along with the rest of the Chagos Archipelago, to the United Kingdom in the Treaty of Paris (1814) at the conclusion of a portion of the Napoleonic Wars.<ref name="Stoddart_209_218"/> Diego Garcia and the Chagos Archipelago were administered by the colonial government on the island of [[British Mauritius|Mauritius]] until 1965, when the UK purchased them from the self-governing colony of Mauritius for £3 million, and declared them to be a separate [[British Overseas Territory]].<ref name="Edis_84">[[#Edis|Edis (2004)]], p. 84.</ref> The [[British Indian Ocean Territory]] administration was moved to [[Seychelles]] following the independence of Mauritius in 1968 until the independence of Seychelles in 1976,<ref name="Edis 2004, p. 80">[[#Edis|Edis (2004)]], p. 80.</ref> and to a desk in the Foreign and Commonwealth Office in London since.<ref>[[#Edis|Edis (2004)]], p. 89.</ref> An agreement signed by the United Kingdom and Mauritius on 22 May 2025, will see sovereignty of the Chagos Archipelago returned to Mauritius on the condition that Diego Garcia will continue to be administered by the United Kingdom for at least 99 years.

===2025 UK–Mauritius Agreement===
Under the terms of the UK–Mauritius Agreement signed in May 2025, Mauritius is to have sovereignty over the Chagos Archipelago in its entirety, including Diego Garcia. The United Kingdom is granted administrative rights over Diego Garcia, including a 12-nautical-mile zone surrounding it, as required to maintain its military bases on the island for a period of at least 99 years. The United Kingdom is responsible for the defence and security of the island. The United Kingdom has criminal and civil jurisdiction in relation to the operation of the bases on the island. Mauritius has jurisdiction over its nationals and persons not connected to the bases. The United Kingdom may not issue coins or postage stamps for the island nor register births, deaths or marriages of persons not connected to the bases. The island's natural and marine resources belong to Mauritius, which also maintains responsibility for environmental conservation and management. Exiled Chagossians and their descendants are not permitted to return to the island.<ref>{{cite web | url=https://www.gov.uk/government/publications/ukmauritius-agreement-concerning-the-chagos-archipelago-including-diego-garcia-cs-mauritius-no12025 | title=UK/Mauritius: Agreement concerning the Chagos Archipelago including Diego Garcia &#91;CS Mauritius No.1/2025&#93; }}</ref>

===Administration as part of the British Indian Ocean Territory===
Diego Garcia is the only inhabited island in the British Indian Ocean Territory, a [[British Overseas Territory]], usually abbreviated as "BIOT". The [[Government of the British Indian Ocean Territory|Government of the BIOT]] consists of a [[Commissioner of the British Indian Ocean Territory|commissioner]] appointed by [[King Charles III]]. The commissioner is based in London, resident in the [[Foreign, Commonwealth and Development Office]] (FCDO), and is assisted by an administrator and small staff.

The UK represents the territory internationally. A local government, comparable to those in other British Overseas Territories, does not exist.<ref>[https://www.cia.gov/the-world-factbook/countries/british-indian-ocean-territory/ CIA World Factbook] {{Webarchive|url=https://web.archive.org/web/20210117034125/https://www.cia.gov/the-world-factbook/countries/british-indian-ocean-territory/ |date=17 January 2021}}, accessed 23 August 2010.</ref> Rather, the administration is represented in the territory by the officer commanding British Forces on Diego Garcia, the "Brit rep". Laws and regulations are promulgated by the commissioner and enforced in the BIOT by Brit rep.

Of major concern to the BIOT administration is the relationship with the United States military forces resident on Diego Garcia. An annual meeting called "The Pol-Mil Talks" (for "political-military") of all concerned is held at the Foreign and Commonwealth Office in London to resolve pertinent issues. These resolutions are formalised by an "Exchange of Letters".<ref name="Sand_24"/>

Neither the US nor the UK recognises Diego Garcia as being subject to the [[African Nuclear Weapons Free Zone Treaty]], which lists BIOT as covered by the treaty.<ref>{{cite web |title=Nuclear-Weapon-Free Zones at a Glance |publisher=Arms Control Association |url=http://www.armscontrol.org/factsheets/nwfz.asp |access-date=28 July 2006 |archive-url=https://web.archive.org/web/20060809134008/http://www.armscontrol.org/factsheets/nwfz.asp |archive-date=9 August 2006 |url-status=live}}</ref><ref name="10.1093/jel/eqn034">{{citation |title=Diego Garcia: British–American Legal Black Hole in the Indian Ocean? |first=Peter H. |last=Sand |date=29 January 2009 |periodical=Journal of Environmental Law |publisher=Oxford Journals |volume=21 |issue=1 |pages=113–137 |doi=10.1093/jel/eqn034}}</ref>  It is not publicly known whether [[nuclear weapon]]s have ever been stored on the island.<ref>{{cite journal |pages=20–21 |url=http://www.unidir.org/files/publications/pdfs/nuclear-weapon-free-zones-en-314.pdf |archive-url=https://web.archive.org/web/20150402163456/http://www.unidir.org/files/publications/pdfs/nuclear-weapon-free-zones-en-314.pdf |archive-date=2 April 2015 |url-status=live |title=The Treaty of Pelindaba: towards the full implementation of the African NWFZ Treaty |author=Noel Stott |journal=Disarmament Forum |year=2011 |access-date=28 February 2015}}</ref> Peter Sand has observed and emphasised that the US and UK stance is blocking the implementation of the treaty.<ref>{{cite journal |url=https://www.asil.org/insights/volume/13/issue/12/african-nuclear-weapon-free-zone-force-what-next-diego-garcia |first=Peter H. |last=Sand |title=African Nuclear-Weapon-Free Zone in Force: What Next for Diego Garcia? |journal=ASIL Insights |volume=3 |issue=12 |date=28 August 2009|publisher=The American Society of International Law|archive-date=1 May 2015|access-date=21 November 2016|archive-url=https://web.archive.org/web/20150501085204/http://www.asil.org/insights/volume/13/issue/12/african-nuclear-weapon-free-zone-force-what-next-diego-garcia|url-status=live}}</ref>

===Transnational political issues===
There are two transnational political issues which affect Diego Garcia and the BIOT, through the British government.

*The island state of Mauritius claims the Chagos Archipelago (which is conterminous with the BIOT), including Diego Garcia. A subsidiary issue is the Mauritian opposition to the UK Government's declaration of 1 April 2010 that the BIOT is a marine protected area with fishing and [[extractivism|extractive industry]] (including oil and gas exploration) prohibited.<ref>[http://www.afriqueavenir.org/en/2010/05/14/mauritius-to-reiterate-its-conditions-for-renewed-talks-with-uk-on-chagos/ "Mauritius to reiterate its conditions for renewed talks with UK on Chagos"], ''Afrique Avenir'', 14 May 2010. {{webarchive |url=https://web.archive.org/web/20111223113708/http://www.afriqueavenir.org/en/2010/05/14/mauritius-to-reiterate-its-conditions-for-renewed-talks-with-uk-on-chagos/ |date=23 December 2011 }}.</ref>
*The issue of compensation and repatriation of the former inhabitants, [[Expulsion of the Chagossians|exiled since 1973]], continues in litigation and as of August 2010 had been submitted to the European Court of Human Rights by a group of former residents.<ref>{{cite news |url=http://www.timesonline.co.uk/tol/news/environment/article7052088.ece |archive-url=https://web.archive.org/web/20110924105418/http://www.timesonline.co.uk/tol/news/environment/article7052088.ece |url-status=dead |archive-date=24 September 2011 |newspaper=[[The Sunday Times]] |access-date=23 August 2010 |title=Chagossians fight for a home in paradise |date=6 March 2010 |first=Catherine|last= Philp}}</ref> Some{{Who|date=June 2012}} groups allege that Diego Garcia and its territorial waters out to {{convert|3|nmi|km|0}} have been restricted from public access without permission of the BIOT Government since 1971.{{citation needed|date=December 2021}}

On 3 November 2022, the British Foreign Secretary [[James Cleverly]] announced that the UK and Mauritius had decided to begin negotiations on sovereignty over the British Indian Ocean Territory, taking into account international legal proceedings. Both states had agreed to ensure the continued operation of the joint UK/US military base on Diego Garcia.<ref name=guardian-20221103>{{cite news |url=https://www.theguardian.com/world/2022/nov/03/uk-agrees-to-negotiate-with-mauritius-over-handover-of-chagos-islands |title=UK agrees to negotiate with Mauritius over handover of Chagos Islands |last=Wintour |first=Patrick |newspaper=The Guardian |date=3 November 2022 |access-date=3 November 2022 |archive-date=3 November 2022 |archive-url=https://web.archive.org/web/20221103141218/https://www.theguardian.com/world/2022/nov/03/uk-agrees-to-negotiate-with-mauritius-over-handover-of-chagos-islands |url-status=live }}</ref><ref name=hansard-20221103>{{cite web |url=https://hansard.parliament.uk/commons/2022-11-03/debates/22110340000007/ChagosArchipelago |title=Chagos Archipelago |last=Cleverly |first=James |publisher=UK Parliament |work=Hansard |id=HCWS354 |date=3 November 2022 |access-date=3 November 2022 |archive-date=4 November 2022 |archive-url=https://web.archive.org/web/20221104013303/https://hansard.parliament.uk/commons/2022-11-03/debates/22110340000007/ChagosArchipelago |url-status=live }}</ref>

===Prison site allegations===
In 2015, U.S. Secretary of State [[Colin Powell]]'s former chief of staff, [[Lawrence Wilkerson]], said Diego Garcia was used by the [[CIA]] for "nefarious activities". He said that he had heard from three US intelligence sources that Diego Garcia was used as "a transit site where people were temporarily housed, let us say, and interrogated from time to time" and, "What I heard was more along the lines of using it as a transit location when perhaps other places were full or other places were deemed too dangerous or insecure, or unavailable at the moment".<ref name="guardian-20150130">{{cite news |url=https://www.theguardian.com/world/2015/jan/30/cia-interrogation-diego-garcia-lawrence-wilkerson |title=CIA interrogated suspects on Diego Garcia, says Colin Powell aide |first=Ian |last=Cobain |newspaper=The Guardian |date=30 January 2015 |access-date=27 February 2015 |archive-date=27 February 2015 |archive-url=https://web.archive.org/web/20150227184955/http://www.theguardian.com/world/2015/jan/30/cia-interrogation-diego-garcia-lawrence-wilkerson |url-status=live }}</ref><ref name="telegraph-20150130">{{cite news |url=https://www.telegraph.co.uk/news/uknews/terrorism-in-the-uk/11380992/Terror-suspects-were-interrogated-on-Diego-Garcia-US-official-admits.html |title=Terror suspects were interrogated on Diego Garcia, US official admits |agency=Press Association |newspaper=Daily Telegraph |date=30 January 2015 |access-date=27 February 2015 |archive-date=28 February 2015 |archive-url=https://web.archive.org/web/20150228020659/http://www.telegraph.co.uk/news/uknews/terrorism-in-the-uk/11380992/Terror-suspects-were-interrogated-on-Diego-Garcia-US-official-admits.html |url-status=live }}</ref>

In June 2004, the British [[Secretary of State for Foreign and Commonwealth Affairs|Foreign Secretary]] [[Jack Straw]] stated that United States authorities had repeatedly assured him that no detainees had passed in transit through Diego Garcia or were disembarked there.<ref>{{Cite journal | title=Written Answers to Questions 21 June 2004 | journal=Hansard House of Commons Daily Debates | volume=422 | issue=part 605 | url=https://publications.parliament.uk/pa/cm200304/cmhansrd/vo040621/text/40621w13.htm#40621w13.html_wqn9 | access-date=21 February 2008 | archive-date=13 May 2006 | archive-url=https://web.archive.org/web/20060513034414/http://www.publications.parliament.uk/pa/cm200304/cmhansrd/vo040621/text/40621w13.htm#40621w13.html_wqn9 | url-status=live }}</ref>

Diego Garcia was first rumoured to have been one of the locations of the [[CIA]]'s [[black sites]] in 2005.<ref>{{cite news |last=Hurst |first=Lynda |date=2 July 2005 |title=Island paradise or torture chamber? |url= |newspaper=[[The Toronto Star]]}}</ref> [[Khalid Sheikh Mohammed]] is one of the "[[high-value detainees]]" suspected to have been held in Diego Garcia.<ref>{{cite news |last=Selsky |first=Andrew |date=16 March 2006 |title=Detainee transcripts reveal more questions |url= |agency=[[Associated Press]]}}</ref> In October 2007, the [[Foreign Affairs Select Committee]] of the British Parliament announced that it would launch an investigation of continued allegations of a prison camp on Diego Garcia, which it claimed were twice confirmed by comments made by retired U.S. Army general [[Barry McCaffrey]].<ref name=guardian>{{Cite news| first1=Ian |last1=Cobain |author2=Richard Norton-Taylor | url=https://www.theguardian.com/usa/story/0,,2194649,00.html | title=Claims of secret CIA jail for terror suspects on British island to be investigated | work=The Guardian | date=19 October 2007 | access-date=21 October 2007 | location=London}}</ref> On 31 July 2008, an unnamed former White House official alleged that the United States had imprisoned and interrogated at least one suspect on Diego Garcia during 2002 and possibly 2003.<ref>{{Cite news| url=http://www.time.com/time/world/article/0,8599,1828469,00.html | archive-url=https://web.archive.org/web/20080805004921/http://www.time.com/time/world/article/0,8599,1828469,00.html | url-status=dead | archive-date=5 August 2008 | magazine=Time | title=Source: US Used UK Isle for Interrogations | date=31 July 2008 | access-date=1 May 2010 | first=Adam | last=Zagorin}}</ref>

[[Manfred Nowak]], one of five [[United Nations special rapporteur]]s on [[torture]], said that credible evidence exists supporting allegations that ships serving as black sites have used Diego Garcia as a base.<ref>{{cite news |url=https://www.theguardian.com/world/2007/oct/19/alqaida.usa |title=Claims of secret CIA jail for terror suspects on British island to be investigated |first1=Ian |last1=Cobain |author2=Richard Norton-Taylor |newspaper=[[The Guardian]] |date=19 October 2007}}</ref> The human rights group [[Reprieve (organisation)|Reprieve]] alleged that United States-operated ships moored outside the [[territorial waters]] of Diego Garcia were used to incarcerate and torture detainees.<ref>{{Cite news| first=Jamie|last= Doward | title=British island 'used by US for rendition' | url=https://www.theguardian.com/world/2008/mar/02/ciarendition.unitednations | work=The Observer | date=2 March 2008 | access-date=27 March 2008 | location=London}}</ref>

===Rendition flight refuelling admission===
Several groups claim that the military base on Diego Garcia has been used by the United States government for transport of prisoners involved in the controversial [[extraordinary rendition]] program, an allegation formally reported to the [[Council of Europe]] in June 2007.<ref>{{Cite report| first=Dick |last=Marty|location= Switzerland, ALDE | title=Secret detentions and illegal transfers of detainees involving Council of Europe member states: second report | version=Section 70; page 13 | publisher=Committee on Legal Affairs and Human Rights | url=http://www.sacc.org.uk/sacc/docs/coe-rendition-second-marty-report.pdf |archive-url=https://web.archive.org/web/20070926201517/http://www.sacc.org.uk/sacc/docs/coe-rendition-second-marty-report.pdf |archive-date=26 September 2007 |url-status=live | date=7 June 2007 | access-date=21 February 2008}}</ref> On 21 February 2008, British Foreign Secretary [[David Miliband]] admitted that two United States extraordinary rendition flights refuelled on Diego Garcia in 2002, and was "very sorry" that earlier denials were having to be corrected.<ref>{{cite news | author=Staff writers | title=UK apology over rendition flights | url=https://news.bbc.co.uk/2/hi/uk_news/politics/7256587.stm | work=BBC News | date=21 February 2008 | access-date=21 February 2008 | archive-date=21 May 2009 | archive-url=https://web.archive.org/web/20090521211747/http://news.bbc.co.uk/1/hi/uk_politics/7256587.stm | url-status=live }}</ref>

===Leaked diplomatic cables===
According to [[United States diplomatic cables leak|leaked diplomatic cables]], in a calculated move planned in 2009, the UK proposed that the BIOT become a "marine reserve" with the aim of preventing the former inhabitants from returning to the islands. A summary of the diplomatic cable is as follows:<ref>{{cite journal |url=http://www.newstatesman.com/blogs/the-staggers/2010/12/british-government-mauritius |title=WikiLeaks, a forgotten people, and the record-breaking marine reserve |first=Sean |last=Carey |date=8 December 2010 |journal=New Statesman |access-date=21 June 2012 |archive-date=5 October 2012 |archive-url=https://web.archive.org/web/20121005232303/http://www.newstatesman.com/blogs/the-staggers/2010/12/british-government-mauritius |url-status=live }}</ref><ref>{{Cite news |date=2 December 2010 |title=US embassy cables: Foreign Office does not regret evicting Chagos islanders |language=en-GB |work=The Guardian |url=https://www.theguardian.com/world/us-embassy-cables-documents/207149 |access-date=23 November 2023 |issn=0261-3077 |archive-date=7 July 2015 |archive-url=https://web.archive.org/web/20150707141257/http://www.theguardian.com/world/us-embassy-cables-documents/207149 |url-status=live }}</ref><blockquote>[[Her Majesty's Government|HMG]] would like to establish a "marine park" or "reserve" providing comprehensive environmental protection to the reefs and waters of the British Indian Ocean Territory (BIOT), a senior Foreign and Commonwealth Office (FCO) official informed Polcouns on 12 May. The official insisted that the establishment of a marine park—the world's largest—would in no way impinge on USG use of the BIOT, including Diego Garcia, for military purposes. He agreed that the UK and United States should carefully negotiate the details of the marine reserve to assure that United States interests were safeguarded and the strategic value of BIOT was upheld. He said that the BIOT's former inhabitants would find it difficult, if not impossible, to pursue their claim for resettlement on the islands if the entire Chagos Archipelago were a marine reserve.</blockquote>

==Natural history==
No species of plant, bird, amphibian, reptile, mollusc, crustacean or mammal is [[endemic]] on Diego Garcia or the surrounding waters, though some species of fish and aquatic invertebrates are endemic. All plants, wildlife, and aquatic species are protected to some degree.

Much of the lagoon and other waters of Diego Garcia are protected wetlands, following an application by the UK in 2004 to obtain [[Ramsar site]] wetlands conservation status,<ref>{{cite web |url=http://www.ukotcf.org/pdf/Ramsar/61BIOT.pdf |archive-url=https://web.archive.org/web/20061005133603/http://www.ukotcf.org/pdf/Ramsar/61BIOT.pdf |archive-date=5 October 2006 |url-status=live |title=Information Sheet on Ramsar Wetlands: Chagos Banks |publisher=United Kingdom Overseas Territories Conservation Forum |date=13 November 2004 |access-date=27 September 2011}}</ref> and large parts of the island are nature preserves.<ref>[[#Sheppard Spalding|Sheppard & Spalding (2003)]], chapter 6.</ref>

===Geography===
[[File:Diego Garcia map - British Indian Ocean Territory.svg|thumb|A location map of Diego Garcia]]
Diego Garcia is the largest land mass in the Chagos Archipelago (which includes [[Peros Banhos]], the [[Salomon Islands]], the [[Three Brothers (islands), Chagos|Three Brothers]], the [[Egmont Islands]], and the [[Great Chagos Bank]]), being an atoll occupying approximately {{convert|174|km2|sqmi|abbr=on|sigfig=2}}, of which {{convert|27.19|km2|sqmi|abbr=on|sigfig=2}} is dry land.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 2.4.1.</ref> The continuous portion of the atoll rim stretches {{convert|64|km|sigfig=2|abbr=in}} from one end to the other, enclosing a lagoon {{convert|21|km|0|abbr=in}} long and up to {{convert|11|km|0|abbr=in}} wide, with a {{convert|6|km|0|adj=on|abbr=off}} pass opening at the north. Three small islands are located in the pass.<ref name="ReferenceA"/>

The island consists of the largest continuous dryland rim of all atolls in the world. The dryland rim varies in width from a few hundred metres to {{convert|2.4|km|abbr=in}}. Typical of coral atolls, it has a maximum elevation on some dunes on the ocean side of the rim of {{convert|9|m|ft|abbr=on}} above mean low water. The rim nearly encloses a lagoon about {{convert|19|km|mi|abbr=in}} long and up to {{convert|8|km|mi|0|abbr=in}} wide. The atoll forms a nearly complete rim of land around a lagoon, enclosing 90% of its [[perimeter]], with an opening only in the north. The main island is the largest of about 60 islands which form the Chagos Archipelago. Besides the main island, three small islets are at the mouth of the lagoon: West Island ({{convert|3.4|ha|acre|abbr=on|disp=or}}), Middle Island ({{convert|6|ha|acre|abbr=on|disp=or}}) and East Island ({{convert|11.75|ha|acre|0|abbr=on|disp=or}}). A fourth, Anniversary Island, {{convert|1|km|yd|0|abbr=in|lk=out}} southwest of Middle Island, appears as just a sand bar on satellite images. Both Middle Island and Anniversary Island are part of the Spur Reef complex.<ref name="ReferenceA">[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 2.5.1.</ref>

The total area of the atoll is about {{convert|170|km2|sqmi|sigfig=2|abbr=on}}. The lagoon area is roughly {{convert|120|km2|sqmi|sigfig=2|abbr=on}} with depths ranging down to about {{convert|25|m|ft|abbr=on}}. The total land area (excluding peripheral reefs) is around {{convert|30|km2|sqmi|sigfig=2|abbr=on}}. The coral reef surrounding the seaward side of the atoll is generally broad, flat, and shallow around {{convert|1|m|ft|abbr=on}} below mean sea level in most locations and varying from {{convert|100|to|200|m|ft|abbr=on}} in width. This fringing seaward reef shelf comprises an area around {{convert|35.2|km2|sqmi|sigfig=2|abbr=on}}. At the outer edge of the reef shelf, the bottom slopes very steeply into deep water, at some locations dropping to more than {{convert|450|m|ft|sigfig=2|abbr=on}} within {{convert|1|km|mi|abbr=on}} of the shore.<ref name="ReferenceA"/>

In the lagoon, numerous coral heads present hazards to navigation. The shallow reef shelf surrounding the island on the ocean side offers no ocean-side anchorage. The channel and anchorage areas in the northern half of the lagoon are [[dredge]]d, along with the pre-1971 ship [[turning basin]]. Significant saltwater wetlands called [[barachois]] exist in the southern half of the lagoon. These small lagoons off of the main lagoon are filled with [[seawater]] at high tide and dry at low tide. Scientific expeditions in 1996 and 2006 described the lagoon and surrounding waters of Diego Garcia, along with the rest of the Chagos Archipelago, as "exceptionally unpolluted" and "pristine".<ref>{{cite web|url=http://www.chagos-trust.org/science.asp |title=Science of the Chagos – Chagos Conservation Trust |access-date=16 June 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090616185943/http://www.chagos-trust.org/science.asp |archive-date=16 June 2009 }}</ref>

Diego Garcia is frequently subject to earthquakes caused by [[tectonic plate]] movement along the [[Carlsberg Ridge]] located just to the west of the island. One was recorded in 1812; one measuring 7.6 on the Richter Scale hit on 30 November 1983, at 11:46&nbsp;pm local time and lasted 72 seconds, resulting in minor damage including wave damage to a {{convert|50|m|adj=on}} stretch of the southern end of the island, and another on 2 December 2002, an earthquake measuring 4.6 on the Richter scale struck the island at 12:21&nbsp;am.<ref name="realhistory" />{{Better source needed|date=July 2023}}

In December 2004, [[2004 Indian Ocean earthquake and tsunami|a tsunami generated near Indonesia]] caused minor shoreline erosion on Barton Point (the northeast point of the atoll of Diego Garcia).<ref>[http://www.reefnewmedia.co.uk/cmt_chagos/uploads/PDF/Newsletters/ChagosNews25.pdf Chagos News, No. 25, p. 2] {{webarchive |url=https://web.archive.org/web/20120119025950/http://www.reefnewmedia.co.uk/cmt_chagos/uploads/PDF/Newsletters/ChagosNews25.pdf |date=19 January 2012 }}</ref>

===Oceanography===
Diego Garcia lies within the influence of the [[South Equatorial Current]] year-round. The surface currents of the Indian Ocean also have a monsoonal regimen associated with the Asian Monsoonal wind regimen.{{Citation needed|date=November 2023}} Sea surface temperatures are in the range of {{convert|80|–|84|F|C|order=flip}} year-round.<ref name="NAVCENT2002">[[#NAVCENT|Local Area Forecaster's Handbook (2002)]], p. 13.</ref>

===Fresh water supply===
Diego Garcia is the above-water rim of a coral atoll composed of [[Holocene]] coral rubble and sand to the depth of about {{convert|36|m|ft fathom|abbr=on}}, overlaying [[Pleistocene]] limestone deposited at the then-sea level on top of a [[seamount]] rising about {{convert|1800|m|ft|abbr=on}} from the floor of the Indian Ocean. The Holocene sediments are porous and completely saturated with sea water. Any rain falling on the above-water rim quickly percolates through the surface sand and encounters the salt water underneath. Diego Garcia is of sufficient width to minimise tidal fluctuations in the [[aquifer]], and the rainfall (in excess of {{convert|2600|mm|in|round=0.5|abbr=in|disp=or}} per year on average)<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 2.5.2.</ref> is sufficient in amount and periodicity for the fresh water to form a series of convex, freshwater, [[Ghyben-Herzberg lenses]] floating on the heavier salt water in the saturated sediments.<ref name="bare_url">{{cite web |url=http://geography.about.com/library/misc/ucghyben.htm |title=Salt Water vs. Fresh Water – Ghyben-Herzberg Lens |publisher=Geography.about.com |date=9 April 2012 |access-date=21 June 2012 |archive-date=5 December 2010 |archive-url=https://web.archive.org/web/20101205001839/http://geography.about.com/library/misc/ucghyben.htm |url-status=dead }}</ref><ref name="Urish">[[#Urish|Urish (1974)]], p. 27.</ref>

The horizontal structure of each lens is influenced by variations in the type and porosity of the subsurface deposits, which on Diego Garcia are minor. At depth, the lens is globular; near the surface, it generally conforms to the shape of the island.<ref>[[#Urish|Urish (1974)]], p. 28.</ref> When a Ghyben-Herzberg lens is fully formed, its floating nature will push a [[Hydraulic head|freshwater head]] above [[mean sea level]], and if the island is wide enough, the depth of the lens below mean sea level will be 40 times the height of the water table above sea level. On Diego Garcia, this equates to a maximum depth of {{convert|20|m|ft fathom|abbr=on}}. However, the actual size and depth of each lens is dependent on the width and shape of the island at that point, the permeability of the aquifer, and the equilibrium between recharging rainfall and losses to evaporation to the atmosphere, transpiration by plants, tidal advection, and human use.

In the plantation period, shallow wells, supplemented by rainwater collected in [[cistern]]s, provided sufficient water for the pastoral lifestyle of the small population. On Diego Garcia today, the military base uses over 100 shallow "horizontal" wells to produce over {{convert|560000|L|abbr=on}} per day from the "Cantonment" lens on the northwest arm of the island—sufficient water for western-style usage for a population of 3,500. This {{convert|3.7|km2|adj=on}} lens holds an estimated {{convert|19|e6m3|abbr=off}} of fresh water and has an average daily recharge from rainfall over {{convert|10000|m3|abbr=in}}, of which 40% remains in the lens and 60% is lost through [[evapotranspiration]].<ref>Hunt, Charles D. "Hydrogeology of Diego Garcia". In: [[#Vacher|Vacher & Quinn (1997)]], pp. 909–929. {{doi|10.1016/S0070-4571(04)80054-2}}.</ref>

Extracting fresh water from a lens for human consumption requires careful calculation of the sustainable yield of the lens by season because each lens is susceptible to corruption by [[saltwater intrusion]] caused by overuse or drought. In addition, overwash by tsunamis and tropical storms has corrupted lenses in the Maldives and several Pacific islands. Vertical wells can cause salt upcoming into the lens, and overextraction will reduce freshwater pressure resulting in lateral intrusion by seawater. Because the porosity of the surface soil results in virtually zero runoff, lenses are easily polluted by fecal waste, burials, and chemical spills. Corruption of a lens can take years to "flush out" and reform, depending on the ratio of recharge to losses.<ref name="bare_url" />

A few natural depressions on the atoll rim capture the abundant rainfall to form areas of freshwater wetlands.<ref name="Stoddart_127_142">D. R. Stoddart (1971): "Land vegetation of Diego Garcia". In: [[#Stoddart|Stoddart & Taylor (1971)]], pp. 127–142.</ref> Two are of significance to island wildlife and to recharge their respective freshwater lenses. One of these is centred on the northwest point of the atoll; another is found near the Point Marianne Cemetery on the southeast end of the airfield. Other, smaller freshwater wetlands are found along the east side of the runway, and in the vicinity of the receiver antenna field on the northwest arm of the atoll.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 3.3.2.1.</ref>

Also, several man-made freshwater ponds resulted from excavations made during construction of the airfield and road on the western half of the atoll rim. These fill from rainfall and from extending into the Ghyben-Herzberg lenses found on this island.<ref>Stephen W. Surface and Edward F.C. Lau, "Fresh Water Supply System Developed on Diego Garcia", The Naval Civil Engineer, Winter 1985</ref>

===Climate===
[[File:Island couple.jpg|thumb|Eclipse Point]]
Diego Garcia has an equatorial [[tropical rainforest climate]] ([[Köppen climate classification|Köppen]] ''Af''). The surrounding sea surface temperature is the primary climatic control, and temperatures are generally uniform throughout the year, with an average maximum of {{convert|30|C|F}} by day during March and April, and {{convert|29|C|F}} from July to September. Diurnal variation is roughly {{convert|3|-|4|C-change|F-change}}, falling to the low {{convert|27|C|F|abbr=on}} by night.<ref name="NAVCENT_2002"/> Humidity is high throughout the year. The almost constant breeze keeps conditions reasonably comfortable.

From December through March, winds are generally westerly around {{convert|6|kn|mph km/h}}. During April and May, winds are light and variable, ultimately backing to an east-southeasterly direction. From June through September, the influence of the Southeast trades is felt, with speeds of {{convert|10|–|15|kn|mph km/h}}. During October and November, winds again go through a period of light and variable conditions veering to a westerly direction with the onset of summer in the Southern Hemisphere.<ref name="NAVCENT_2002"/>

All [[precipitation]] falls as [[rain]], characterised by air mass-type showers. Annual rainfall averages {{convert|2603.5|mm|in|abbr=on}}, with the heaviest precipitation from September to April. January is the wettest month with {{convert|353|mm|in|abbr=on}} of mean monthly precipitation, and August the driest month, averaging {{convert|106.5|mm|in|abbr=on}} of mean monthly precipitation.<ref name="NAVCENT_2002"/>

[[Thunderstorm]] activity is generally noticed in the afternoon and evening during the summer months (December through March), when the [[Intertropical Convergence Zone]] is in the vicinity of the island.<ref name="NAVCENT_2002">[[#NAVCENT|Local Area Forecaster's Handbook (2002)]], p. 14.</ref>

Diego Garcia is at minimum risk from [[tropical cyclone]]s due to its proximity to the [[equator]] where the [[Coriolis effect|coriolis parameter]] required to organise circulation of the [[upper atmosphere]] is minimal. Low-intensity storms have hit the island, including one in 1901, which blew over 1,500 coconut trees;<ref>[[#Edis|Edis (2004)]], p. 71.</ref> one on 16 September 1944,<ref>{{cite web |first=Ted |last=Morris |url=http://www.zianet.com/tedmorris/dg/pby.html |title=Diego Garcia – The PBY Catalina |publisher=Zianet.com |date=19 September 2002 |access-date=21 June 2012 |archive-date=12 May 2011 |archive-url=https://web.archive.org/web/20110512172819/http://www.zianet.com/tedmorris/dg/pby.html |url-status=live }}</ref>{{Better source needed|date=July 2023}} which caused the wreck of a Royal Air Force PBY Catalina; one in September 1990 which demolished the tent city then being constructed for United States Air Force bomber crews during Operation Desert Storm;<ref name="realhistory">{{cite web |url=http://www.zianet.com/tedmorris/dg/realhistory.html |title=Important Dates of the Provisional People's Democratic Republic of Diego Garcia |access-date=27 September 2011 |date=29 August 2011 |archive-date=11 June 2011 |archive-url=https://web.archive.org/web/20110611005507/http://www.zianet.com/tedmorris/dg/realhistory.html |url-status=live }}</ref>{{Better source needed|date=July 2023}} and one on 22 July 2007, when winds exceeded {{convert|60|kn|mph km/h}} and over {{convert|250|mm|in|0|abbr=on}} of rain fell in 24 hours.<ref name="realhistory"/>{{Better source needed|date=July 2023}}

[[File:Degar sunset from cannon point.jpg|thumb|left|Sunset at Cannon Point]]
The island was somewhat affected by the [[tsunami]] caused by the [[2004 Indian Ocean earthquake]]. Service personnel on the western arm of the island reported only a minor increase in wave activity. The island was protected to a large degree by its favourable [[ocean topography]]. About {{convert|80|km|mi|abbr=in}} east of the atoll lies the {{convert|650|km|mi|abbr=off|adj=mid|-long}} Chagos Trench, an underwater canyon plunging more than {{convert|4900|m|ft|abbr=on}}. The depth of the trench and its grade to the atoll's slope and shelf shore makes it more difficult for substantial tsunami waves to build before passing the atoll from the east. In addition, near-shore [[coral reef]]s and an algal platform may have dissipated much of the waves' impact.<ref>[http://www.estripes.com/article.asp?section=104&article=26265 "Diego Garcia Navy base reports no damage from quake, tsunamis"] {{webarchive|url=https://web.archive.org/web/20110927024535/http://www.estripes.com/article.asp?section=104&article=26265 |date=27 September 2011 }}. Leo Shane&nbsp;III, ''Stars and Stripes''. 28 December 2004. URL accessed 1 June 2006.</ref><ref name=chagosnews>{{Cite journal|last=Sheppard |first=Charles |title=The Tsunami, Shore Erosion and Corals in the Chagos Islands |journal=Chagos News |volume=25 |pages=2–7 |issn=1355-6746 |date=April 2005 |url=http://www.chagosconservationtrust.org/pages/Chagos%20News/ChagosNews25.pdf |access-date=21 February 2008 |url-status=dead |archive-url=https://web.archive.org/web/20081003104800/http://www.chagosconservationtrust.org/pages/Chagos%20News/ChagosNews25.pdf |archive-date=3 October 2008 }}</ref> A biological survey conducted in early 2005 indicated erosional effects of the tsunami wave on Diego Garcia and other islands of the Chagos Archipelago. One {{convert|200|to|300|m|yd|adj=on|abbr=on}} stretch of shoreline was found to have been breached by the tsunami wave, representing about 10% of the eastern arm. A biological survey by the Chagos Conservation Trust reported that the resulting inundation additionally washed away shoreline shrubs and small to medium-sized coconut palms.<ref name=chagosnews/>

{{Weather box
|location = Diego Garcia (extremes 1951–2021)
|metric first = yes
|single line = yes
|collapsed = Y
|width = auto
|Jan record high C = 36.1
|Feb record high C = 37.2
|Mar record high C = 36.1
|Apr record high C = 35.0
|May record high C = 36.1
|Jun record high C = 35.0
|Jul record high C = 33.0
|Aug record high C = 32.4
|Sep record high C = 34.2
|Oct record high C = 34.9
|Nov record high C = 35.1
|Dec record high C = 37.2
|year record high C = 37.2
|Jan high C = 29.8
|Feb high C = 30.3
|Mar high C = 30.9
|Apr high C = 30.9
|May high C = 30.2
|Jun high C = 29.4
|Jul high C = 28.7
|Aug high C = 28.7
|Sep high C = 29.0
|Oct high C = 29.4
|Nov high C = 29.8
|Dec high C = 30.1
|year high C = 29.7
|Jan mean C = 27.1
|Feb mean C = 27.4
|Mar mean C = 27.6
|Apr mean C = 27.8
|May mean C = 27.5
|Jun mean C = 26.8
|Jul mean C = 26.3
|Aug mean C = 26.1
|Sep mean C = 26.4
|Oct mean C = 26.7
|Nov mean C = 27.0
|Dec mean C = 27.2
|year mean C = 27.0
|Jan low C = 24.7
|Feb low C = 25.0
|Mar low C = 25.4
|Apr low C = 25.7
|May low C = 25.4
|Jun low C = 24.7
|Jul low C = 24.2
|Aug low C = 24.1
|Sep low C = 24.2
|Oct low C = 24.3
|Nov low C = 24.7
|Dec low C = 24.8
|year low C = 24.8
|Jan record low C = 20.0
|Feb record low C = 20.0
|Mar record low C = 17.8
|Apr record low C = 21.1
|May record low C = 17.8
|Jun record low C = 17.8
|Jul record low C = 17.2
|Aug record low C = 20.0
|Sep record low C = 21.1
|Oct record low C = 16.1
|Nov record low C = 21.7
|Dec record low C = 18.3
|year record low C = 16.1
|rain colour = green
|Jan rain mm = 340
|Feb rain mm = 279
|Mar rain mm = 213
|Apr rain mm = 194
|May rain mm = 167
|Jun rain mm = 147
|Jul rain mm = 144
|Aug rain mm = 145
|Sep rain mm = 244
|Oct rain mm = 281
|Nov rain mm = 221
|Dec rain mm = 273
|year rain mm = 2648
|unit rain days = 0.3 mm
|Jan rain days = 22
|Feb rain days = 19
|Mar rain days = 18
|Apr rain days = 17
|May rain days = 15
|Jun rain days = 15
|Jul rain days = 17
|Aug rain days = 16
|Sep rain days = 16
|Oct rain days = 20
|Nov rain days = 19
|Dec rain days = 20
|year rain days = 212
|Jan humidity = 80
|Feb humidity = 79
|Mar humidity = 78
|Apr humidity = 77
|May humidity = 79
|Jun humidity = 79
|Jul humidity = 79
|Aug humidity = 79
|Sep humidity = 80
|Oct humidity = 79
|Nov humidity = 79
|Dec humidity = 78
|year humidity = 79
|source 1 = [[Deutscher Wetterdienst]]<ref name = DWD>{{cite web
| url = http://www.dwd.de/DWD/klima/beratung/ak/ak_619670_kt.pdf
| title = Klimatafel von Diego Garcia, Chagos-Archipel / Indischer Ozean / Großbritannien
| work = Baseline climate means (1961–1990) from stations all over the world
| publisher = Deutscher Wetterdienst
| language = de
| access-date = 18 October 2016
| archive-date = 2 April 2019
| archive-url = https://web.archive.org/web/20190402152842/https://www.dwd.de/DWD/klima/beratung/ak/ak_619670_kt.pdf
| url-status = live
}}</ref>
|source 2 =  Meteo Climat (record highs and lows)<ref name = meteoclimat>{{cite web
| url = http://meteo-climat-bzh.dyndns.org/index.php?page=stati&id=1983
| title = Station Diego Garcia
| publisher = Meteo Climat
| language = fr
| access-date = 26 August 2021
| archive-date = 24 February 2021
| archive-url = https://web.archive.org/web/20210224213049/http://meteo-climat-bzh.dyndns.org/index.php?page=stati&id=1983
| url-status = live
}}</ref>
}}

===Vegetation===
[[File:Diego Garcia Mixed Species Marsh.png|thumb|A mixed-species freshwater wetland on Diego Garcia]]

The first [[botanical]] observations of the island were made by Hume in 1883, when the coconut plantations had been in operation for a full century. Subsequent studies and collections during the plantation era were made in 1885, 1905, 1939, and 1967.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 1.</ref> Thus, very little of the nature of the precontact vegetation is known.

The 1967 survey, published by the [[Smithsonian]]<ref>[[#Stoddart|Stoddart & Taylor (1971)]]{{page needed|date=September 2011}}</ref> is used as the most authoritative baseline for more recent research. These studies indicate the vegetation of the island may be changing rapidly. For example, J. M. W. Topp collected data annually between 1993 and 2003 and found that on the average three new plant species arrived each year, mainly on Diego Garcia. His research added fully a third more species to Stoddart.<ref>[[#Topp|Topp (1988)]], p. 2.</ref> Topp and Martin Hamilton of [[Kew Gardens]] compiled the most recent checklist of vegetation in 2009.<ref>[[#Hamilton|Hamilton & Topp (2009)]]</ref>

[[File:Diego Garcia Cocos Forest.png|thumb|left|upright|A thick forest of coconuts on Diego Garcia]]
In 1967, Stoddart described the land area of Diego Garcia as having a [[littoral]] [[hedge]] of ''[[Scaevola taccada]]'', while inland, ''[[Cocos nucifera]]'' (coconut) was the most dominant tree, covering most of the island. The substory was either managed and park-like, with understory less than 0.5 m in height, or consisted of what he called "Cocos Bon-Dieu"&nbsp;– an intermediate story of juvenile trees and a luxuriant ground layer of self-sown seedlings&nbsp;– causing those areas to be relatively impenetrable.<ref name="Stoddart_143_160">F. R. Fosberg & A. A. Bullock (1971): "List of Diego Garcia vascular plants". In: [[#Stoddart|Stoddart & Taylor (1971)]], pp. 143–160.</ref>

Also, areas of remnant tropical hardwood forest are at the sites of the plantation-era villages, as well as ''[[Casuarina equisetifolia]]'' (iron wood pines) woodlands.<ref name="Stoddart_127_142"/>

In 1997, the United States Navy contracted a vegetation survey that identified about 280 species of terrestrial [[vascular plant]]s on Diego Garcia.<ref>[[#Sheppard Seaward|Sheppard & Seaward (1999)]], p. 225.</ref> None of these was [[endemic]], and another survey in 2005 identified just 36 species as "native", meaning arriving without the assistance of humans, and found elsewhere in the world.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E2, paragraph E2-2.</ref> No [[terrestrial plant]] species are of any conservation-related concern at present.<ref>[[#Sheppard Spalding|Sheppard & Spalding (2003)]], p. 40.</ref>
[[File:Diego Garcia Hernandia Forest.png|thumb|A ''Hernandia''-dominated forest on Diego Garcia]]

Of the 36 native vascular plants on Diego Garcia, 12 are trees, five are [[shrub]]s, seven are [[dicotyledon]] herbs, three are grasses, four are [[vine]]s, and five are [[fern]]s.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 4-3.</ref>

The 12 tree species are: ''[[Barringtonia asiatica]]'' (fish-poison tree), ''[[Calophyllum inophyllum]]'' (Alexandrian laurel), ''[[Cocos nucifera]]'', ''[[Cordia subcordata]]'', ''[[Guettarda speciosa]]'', ''[[Intsia bijuga]]'', ''[[Hernandiaceae|Hernandia sonora]]'', ''[[Morinda citrifolia]]'', ''[[Neisosperma oppositifolium]]'',<ref>{{cite web|url=http://www.ars-grin.gov/~sbmljw/cgi-bin/taxon.pl?412139 |archive-url=https://web.archive.org/web/20150903221255/http://www.ars-grin.gov/~sbmljw/cgi-bin/taxon.pl?412139 |url-status=dead |archive-date=3 September 2015 |title=''Neisosperma oppositifolium'' (Lam.) Fosberg & Sachet |publisher=[[United States Department of Agriculture]] |work=[[Germplasm Resources Information Network]] |access-date=27 September 2011 }}</ref> ''[[Pisonia grandis]]'', ''[[Terminalia catappa]]'', and ''[[Heliotropium foertherianum]]''. Another three tree species are common, and may be native, but they may also have been introduced by humans: ''Casuarina equisetifolia'', ''[[Hibiscus tiliaceus]]'', and ''[[Pipturus|Pipturus argenteus]]''.

The five native shrubs are: ''[[Caesalpinia bonduc]]'', ''[[Pemphis|Pemphis acidula]]'', ''[[Premna|Premna serratifolia]]'', ''Scaevola taccada'' (often mispronounced "Scaveola"), and ''[[Suriana maritima]]''.

[[File:Premna Shrubland.png|thumb|right|A ''Premna''-dominated scrub land on Diego Garcia]]
Also, 134 species of plants are classified as "weedy" or "naturalised alien species", being those unintentionally introduced by man, or intentionally introduced as ornamentals or crop plants which have now "gone native", including 32 new species recorded since 1995, indicating a very rapid rate of introduction.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 4-5.</ref> The remainder of the species list consists of cultivated food or ornamental species, grown in restricted environments such as a planter's pot.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 4-6.</ref>

[[File:Diego Garcia Cattail Marsh.png|thumb|upright|A freshwater marsh composed entirely of cattails located on the eastern edge of the bomber ramp on Diego Garcia]]

[[File:Diego Garcia Littoral Scrub 1.png|thumb|A typical oceanside littoral hedge with ''Casuarina'' fringe]]

In 2004, 10 [[plant communities]] were recognised on the atoll rim:<ref name="ReferenceA"/>
* ''Calophyllum'' forest, dominated by ''Calophyllum inophyllum'', with trunks that can grow in excess of {{convert|2|m|ft|abbr=on}} in diameter. This forest often contains other species such as ''Hernandia sonora'', ''Cocos nucifera'', and ''Guettarda speciosa'' with a ''Premna obtusifolia'' edge. When found on the beaches, ''Calophyllum'' often extends over the lagoon water and supports nesting red-footed boobies, as does ''Barringtonia asiatica'' found mostly on the eastern arm of the atoll.
* ''Cocos'' forest, essentially monotypic (''Cocos bon Dieu''), with the understory consisting of coconut seedlings
* ''Cocos-Hernandia'' forest, dominated by two canopy species—''C. nucifera'' and ''H. sonora''
* ''Cocos-Guettarda'' forest, dominated by the canopy species ''C. nucifera'' and ''G. speciosa'': The understory consists of a mix of ''Neisosperma oppositifolium'', with ''Scaevola taccada'' and ''Tournefortia argentea'' on the beach edge.
* ''Hernandia'' forest, dominated at the canopy level by ''H. sonora'': The most representative areas of this forest type are on the eastern, undeveloped part of the atoll. ''Calophyllum inophyllum'' and ''C. nucifera'' are often present. Understory species in this forest are often ''Morinda citrifolia'', ''Cocos'' seedlings, and ''[[Asplenium nidus]]'' (bird's nest fern), and occasionally, ''N. oppositifolium'' and ''G. speciosa''.
* ''Premna'' shrubland, occurring generally between marshy areas and forested areas: The most conspicuous vegetation is primarily ''P. obtusifolia'', with ''Casuarina equisetifolia'' and ''Scaevola taccada'' on the margins. The dense groundcover consists of species such as ''[[Fimbristylis|Fimbristylis cymosa]]'', ''[[Ipomoea pes-caprae]]'' (beach morning glory) and ''[[Triumfetta|Triumfetta procumbens]]''. ''Premna'' shrubland appears mostly adjacent to the developed areas of the atoll, particularly in the well fields.
* Littoral scrub lines almost the entire seashore and lagoon shore of the island. It is dominated by ''S. taccada'', but it also contains scattered coconut trees, ''G. speciosa'' and ''Pisonia grandis''. On the seaward side, it also contains ''Tournefortia argentea'' and ''Suriana maritima''. On the lagoon side, it may also contain ''[[Lepturus|Lepturus repens]]'', ''[[Triumfetta|Triumfetta procumbens]]'' and ''[[Cyperus|Cyperus ligularis]]''. Large pockets of ''Barringtonia asiatica'' are also on the eastern edge of the lagoon.
* Maintained areas of grasses and sedges routinely mowed: Aerial photographs of the island clearly display large areas of grasslands and park-like [[savanna]] upon which the United States military has constructed large outdoor facilities such as antenna fields and the airport.<ref>{{cite web |author=President for Life |url=http://www.zianet.com/tedmorris/dg/aerial2.html |title=Aerial Photographs of Diego Garcia |publisher=Zianet.com |access-date=21 June 2012 |archive-date=11 June 2011 |archive-url=https://web.archive.org/web/20110611010333/http://www.zianet.com/tedmorris/dg/aerial2.html |url-status=live }}</ref>{{Better source needed|date=July 2023}}
* Mixed native forest, with no dominant canopy species
* Marshes are divided into three different types: cattail (''[[Typha domingensis]]''), wetland, and mixed species. Cattail marshes contained almost entirely cattails. These areas are often man-made reservoirs or drainages that have been almost entirely monotypic. Wetlands were based upon vegetation that occurred in the area with fresh water. Mixed-species marshes were highly variable and usually had no standing water.

===Wildlife===
[[File:Coconut Crab.jpg|thumb|[[Coconut crab]]s are protected on Diego Garcia.]]
All the terrestrial and aquatic fauna of Diego Garcia are protected, with the exception of certain game fish, rats, and cats; hefty fines are levied against violators.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix B.</ref>

====Crustaceans====
The island is a haven for several types of [[crustacean]]; "warrior crabs" (''[[Cardisoma carnifex]]'') overrun the jungle at night. The extremely large {{convert|4|kg|lb|adj=on}} [[coconut crab]] or robber crab (''Birgus latro'') is found here in large numbers. Because of the protections provided the species on this atoll, and the isolation of the east rim of the atoll, the species is recorded in greater densities there than anywhere else in its range (339 crabs/ha).<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix G, p. G-7.</ref>

====Mammals====
No [[mammal]] species are native on Diego Garcia, with no record of bats.<ref name="Stoddart_163_170">Stoddarrt, D. R. (1971): "Terrestrial fauna of Diego Garcia and other Chagos atolls". In: [[#Stoddart|Stoddart & Taylor (1971)]], pp. 163–170.</ref> Other than rats (''[[Rattus rattus]]''), all "wild" mammal species are feral descendants of domesticated species. During the plantation era, Diego Garcia was home to large herds of Sicilian donkeys (''[[Equus asinus]]''), dozens of horses (''[[Equus caballus]]''), hundreds of dogs (''[[Canis familiaris]]''), and house cats (''[[Felis catus]]''). In 1971, the BIOT Commissioner ordered the extermination of [[feral dogs]] following the departure of the last plantation workers, and the program continued through 1975, when the last feral dog was observed and shot.<ref>Bruner, Phillip, "Avifaunal and Feral Mammal Survey of Diego Garcia, Chagos Archipelago, British Indian Ocean Territory", 17 October 1995, pp. 3–23.</ref> Donkeys, which numbered over 400 in 1972, were down to just 20 individuals in 2005.<ref name="NRMP_G_4_27">[[#NRMP|Natural Resources Management Plan (2005)]], Appendix G, p. 4.27.</ref> The last horse was observed in 1995,<ref name="NRMP_G_4_27"/> and by 2005, just two cats were thought to have survived an island-wide eradication program.{{Citation needed|date=August 2010}}

====Native birds====
[[File:Red-tailed Tropicbird3.jpg|thumb|left|Several pairs of [[red-tailed tropicbird]] nest near the cantonment area.]]

The total bird list for the Chagos Archipelago, including Diego Garcia, consists of 91 species, with large breeding populations of 16 species. Although no birds are endemic, internationally important seabird colonies exist. Diego Garcia's seabird community includes thriving populations of species which are rapidly declining in other parts of the Indian Ocean. Large nesting colonies of [[brown noddies]], [[bridled tern]]s, the [[lesser noddy]], [[red-footed booby]] and [[lesser frigatebird]]s exist on Diego Garcia.

Other nesting native birds include [[red-tailed tropicbird]]s, [[wedge-tailed shearwater]]s, [[tropical shearwater]], [[black-naped tern]]s, [[white tern]]s, [[striated heron]]s, and [[white-breasted waterhen]]s.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 4.2.2.1.1.</ref> The 680-hectare [[Barton Point Nature Reserve]] was identified as an [[Important Bird Area]] for its large breeding colony of red-footed boobies.<ref>{{cite web|url=http://www.birdlife.org |title=Barton Point Nature Reserve |access-date=21 October 2012 |work=Important Bird Areas factsheet |publisher=BirdLife International |year=2012 |url-status=dead |archive-url=https://web.archive.org/web/20070710124603/http://www.birdlife.org/ |archive-date=10 July 2007 }}</ref>

====Introduced birds====
The island hosts introduced bird species from many regions, including cattle egrets (''[[Bubulcus ibis]]''), Indian barred ground dove, also called the zebra dove (''[[Geopelia striata]]''), turtle dove (''[[Nesoenas picturata]]''), Indian mynah (''[[Acridotheres tristis]]''), Madagascar fody (''[[Foudia madagascariensis]]''), and chickens (''[[Gallus gallus]]'').<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 4.2.2.1.3.</ref>
{{Clear left}}

====Terrestrial reptiles and freshwater amphibians====
Currently, three lizards and one toad are known to inhabit Diego Garcia, and possibly one snake. All are believed to have been introduced by human activity. The house gecko (''[[Hemidactylus frenatus]]''), the mourning gecko (''[[Lepidodactylus lugubris]]''), the garden lizard (an agamid) (''[[Calotes versicolor]]''), and the cane toad (''[[Bufo marinus]]'').<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 4.2.2.6.</ref> A viable population of a type of blind snake from the family Typhlopidae may be present, probably the brahminy blind snake (''[[Ramphotyphlops braminus]]''). This snake feeds on the larvae, eggs, and pupae of [[ant]]s and [[termite]]s, and is about the size of a large earthworm.

====Sea turtles====
Diego Garcia provides suitable foraging and nesting habitat for both the hawksbill turtle (''[[Eretmochelys imbricata]]'') and the green turtle (''[[Chelonia mydas]]''). Juvenile hawksbills are quite common in the lagoon and at Barachois Sylvane (also known as Turtle Cove) in the southern part of the lagoon. Adult hawksbills and greens are common in the surrounding seas and nest regularly on the ocean-side beaches of the atoll. Hawksbills have been observed nesting during June and July, and from November to March. Greens have been observed nesting in every month; the average female lays three clutches per season, each having an average clutch size of 113 eggs. [[Diurnality|Diurnal]] nesting is common in both species. An estimated 300–700 hawksbills and 400–800 greens nest in the Chagos.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix K, pp. K-2–K-3.</ref>

====Endangered species====
Four reptiles and six cetaceans are endangered and may or may not be found on or around Diego Garcia:<ref>[[#NRMP|Natural Resources Management Plan (2005)]], paragraph 4.4.</ref>
Hawksbill turtle (''[[hawksbill turtle|Eretmocheyls imbricata]]'') – known; leatherback turtle (''[[Dermochelys coriacea]]'') – possible; green turtle (''Chelonia mydas'') – known; olive ridley turtle (''[[olive ridley|Lepidochelys oliveacea]]'') – possible; sperm whale (''[[Physeter macrocephalus]]'') – possible; sei whale (''[[Sei whale|Balaeonoptera borealis]]'') – possible;
finback whale (''[[Fin whale|Balaeonoptera physalus]]'') – possible; Bryde's whale (''[[Bryde's whale|Balaeonoptera edeni]]'') – possible; blue whale (''[[blue whale|Balaeonoptera musculus]]'') – possible; humpback whale (''[[Megaptera novaeangliae]]'') – possible; southern right whale (''[[Eubalaena australis]]'') – possible.<ref>Carroll L.E.. 2011. [https://researchspace.auckland.ac.nz/bitstream/handle/2292/11541/whole.pdf?sequence=9 Return of the Right Whale: Assessment of Abundance, Population Structure and Geneflow in the New Zealand Southern Right Whale] {{Webarchive|url=https://web.archive.org/web/20160304134152/https://researchspace.auckland.ac.nz/bitstream/handle/2292/11541/whole.pdf?sequence=9 |date=4 March 2016 }}. [[University of Auckland]]. Retrieved on 25 November 2015</ref>

==United Kingdom military activities==
{{main|British Forces British Indian Ocean Territories|Naval Support Facility Diego Garcia}}

British Forces British Indian Ocean Territories (BFBIOT) is the official name for [[His Majesty's Armed Forces]] (HMAF) deployment at the Permanent Joint Operating Base (PJOB) on Diego Garcia, in the British Indian Ocean Territory (BIOT).<ref name="PJOB">[https://www.gov.uk/government/publications/permanent-joint-operating-bases-pjobs/permanent-joint-operating-bases-pjobs Permanent Joint Operating Bases (PJOBs)] {{Webarchive|url=https://web.archive.org/web/20160322052411/https://www.gov.uk/government/publications/permanent-joint-operating-bases-pjobs/permanent-joint-operating-bases-pjobs |date=22 March 2016 }}, www.gov.uk, 12 December 2012</ref> While the naval and airbase facilities on Diego Garcia are leased to the United States, in practice, it operates as a joint UK-US base, with the UK retaining full and continual access.<ref name=europarl>{{cite journal|title=The Status and Location of the Military Installations of the Member States of the European Union|journal=Policy Department External Policies|date=February 2009|pages=13–14|url=http://www.europarl.europa.eu/meetdocs/2004_2009/documents/dv/sede300309studype407004_/SEDE300309StudyPE407004_en.pdf|access-date=21 October 2014|archive-date=24 September 2015|archive-url=https://web.archive.org/web/20150924052522/http://www.europarl.europa.eu/meetdocs/2004_2009/documents/dv/sede300309studype407004_/SEDE300309StudyPE407004_en.pdf|url-status=live}}</ref> Diego Garcia is strategically located, offering access to East Africa, the Middle East and Southeast Asia. The base serves as a staging area for the buildup or resupply of military forces prior to an operation. There are approximately 40–50 British military personnel posted on Diego Garcia, most of them from [[Naval Party (Royal Navy)|Naval Party 1002]] (NP1002). NP1002 forms the island's civil administration and some [[Royal Navy|naval forces]].<ref>[http://www.public.navy.mil/fcc-c10f/nctsfedetdg/Documents/WELCOME_ABOARD_JAN%202011_.pdf Welcome to Diego Garcia] {{Webarchive|url=https://web.archive.org/web/20161005191638/http://www.public.navy.mil/fcc-c10f/nctsfedetdg/Documents/WELCOME_ABOARD_JAN%202011_.pdf |date=5 October 2016 }}, page 3, DIEGO GARCIA, A BRITISH TERRITORY, public.navy.mil</ref>

==United States military activities==
{{Main|Naval Support Facility Diego Garcia}}

[[File:Diego Garcia Island Map.jpg|thumb|A map of military installations on Diego Garcia in 2002]]

During the [[Cold War]] era, following the British withdrawal from East of Suez, the United States was keen to establish a military base in the Indian Ocean to counter Soviet influence and establish American dominance in the region and protect its sea-lanes for oil transportation from the Middle East. The United States saw the atoll as the "Malta of the Indian Ocean" equidistant from all points.<ref>[[#Ladwig|Ladwig, Erickson and Mikolay (2014)]], pp. 138–42.</ref> The island has served as an "[[unsinkable aircraft carrier]]" for United States activities during the [[Iranian revolution]], the [[Iraqi invasion of Kuwait]], [[Operation Desert Fox]], [[Operation Enduring Freedom]], and [[Operation Iraqi Freedom]]. In the contemporary era, the atoll retains a key role in America's strategic approach to the Indian Ocean, acting as a flexible forward military hub able to support a range of offensive activities.<ref name="Ladwig2">Walter C. Ladwig III {{cite web|url=http://www.walterladwig.com/Articles/A%20Neo-Nixon%20Doctrine%20for%20the%20Indian%20Ocean.pdf |title=A Neo-Nixon Doctrine for the Indian Ocean: Helping States Help Themselves |work=Strategic Analysis |volume=36 |issue=3 |date=May 2012 |url-status=live |archive-url=https://web.archive.org/web/20170608192511/http://www.walterladwig.com/Articles/A%20Neo-Nixon%20Doctrine%20for%20the%20Indian%20Ocean.pdf |archive-date=8 June 2017 |access-date=8 June 2017}}</ref><ref name="YoHolmes">James R. Holmes & Toshi Yoshihara{{Cite journal|title= An Ocean Too Far: Offshore Balancing in the Indian Ocean |journal= Asian Security |volume=8 |issue=1 |pages= 1–26 |date=March 2012|doi= 10.1080/14799855.2011.652025 |last1= Holmes |first1= James R |last2= Yoshihara |first2= Toshi |s2cid= 153355074 }}</ref> American [[gunship]]s based off the island participated in [[War in Somalia (2006–2009)|Ethiopia's invasion of Somalia]] in late 2006.<ref>{{Cite journal |last=Otieno |first=Orwa Michael |date=2010-05-20 |title=The U.S.–Africa Command and Pan-African Resistance |url=http://www.tandfonline.com/doi/full/10.1080/10402651003751362 |journal=Peace Review |language=en |volume=22 |issue=2 |pages=136–143 |doi=10.1080/10402651003751362 |issn=1040-2659 |s2cid=146737860 |quote=Such was the case in 2006 when Ethiopia, backed by U.S. technical support and firepower from U.S. gunships based in Diego Garcia, invaded Somalia to rout the Union of Islamic Courts|url-access=subscription }}</ref>

The United States military facilities on Diego Garcia have been known informally as [[Camp Justice (Diego Garcia)|Camp Justice]]<ref name=UsnDiegoGarcia20031304>{{cite news | url=http://www.navy.mil/search/display.asp?story_id=10894 | title=Liberty Hall One Step Closer to a Cool Summer | publisher=[[United States Navy]] | first=Jeffrey|last= Fretland | date=4 December 2003 | access-date=14 October 2007 | archive-date=29 June 2011 | archive-url=https://web.archive.org/web/20110629052717/http://www.navy.mil/search/display.asp?story_id=10894 | url-status=dead }}</ref><ref name=UsnDrewCarey20021230>{{cite news | url=http://www.navy.mil/search/display.asp?story_id=5218 | title=Comedian Visits Troops on Remote Isle | publisher=[[United States Navy]] | first=Jeremy L. |last=Wood | date=30 December 2002 | access-date=14 October 2007 | archive-date=29 June 2011 | archive-url=https://web.archive.org/web/20110629052727/http://www.navy.mil/search/display.asp?story_id=5218 | url-status=dead }}</ref><ref name=UsnDiegoBase>{{cite news|url=http://www.dg.navy.mil/web/index.htm |title=United States Navy Diego Garcia Support Facility |publisher=[[United States Navy]] |access-date=14 October 2007 |url-status=dead |archive-url=https://web.archive.org/web/20071010055354/http://www.dg.navy.mil/web/index.htm |archive-date=10 October 2007 }}</ref> and, after renaming in July 2006, as [[Camp Thunder Cove]].<ref name=DefendAmerica20060726>{{cite news|url=http://www.defendamerica.mil/articles/jul2006/a072606ls1.html |title='Camp Justice' Becomes 'Thunder Cove': Airmen of 40th Air Expeditionary Group give tent city a new name |publisher=[[United States Department of Defense]] |first=Jason|last= Smith |date=26 July 2006 |access-date=14 October 2007 |url-status=dead |archive-url=https://web.archive.org/web/20140105060627/http://www.defendamerica.mil/articles/jul2006/a072606ls1.html |archive-date=5 January 2014 }}</ref> Formally, the base is known as [[Naval Support Facility Diego Garcia]] (the US activity) or Permanent Joint Operating Base (PJOB) Diego Garcia (the UK's term).<ref>[[#Ladwig|Ladwig, Erickson and Mikolay (2014)]], pp. 141–3.</ref>

United States military activities in Diego Garcia have caused friction between India and the United States in the past.<ref>[[#Ladwig|Ladwig, Erickson and Mikolay (2014)]], pp. 155.</ref>  Political party [[CPI(M)]] in India has<ref name="Yechury">{{Cite journal | first=Sitaram | last=Yechury | title=Access to Indian Military Bases: Making India an Appendage to US | journal=People's Democracy | url=http://pd.cpim.org/2001/july01/july012k1_indo_us.htm | volume=XXV | issue=26 | date=1 July 2001 | access-date=27 March 2008 | archive-url=https://web.archive.org/web/20070314000846/http://pd.cpim.org/2001/july01/july012k1_indo_us.htm | archive-date=14 March 2007 | url-status=dead }}</ref> repeatedly called for the military base to be dismantled, as they saw the United States naval presence in Diego Garcia as a hindrance to peace in the Indian Ocean.<ref name="Yechury"/> In recent years, relations between India and the United States have improved dramatically. Diego Garcia was the site of several naval exercises between the United States and [[Indian Navy|Indian]] navies held between 2001 and 2004.<ref>[[#Ladwig|Ladwig, Erickson and Mikolay (2014)]], pp. 156.</ref><ref>{{Cite news | url=http://www.accessmylibrary.com/coms2/summary_0286-25566204_ITM | work=Asia Africa Intelligence Wire | title=Mauritius may relent on US base in Diego Garcia | date=13 April 2002 | archive-date=22 May 2015 | access-date=9 August 2008 | archive-url=https://archive.today/20150522073521/https://www.questia.com/ | url-status=live }}</ref>

Recent construction in support of US military activities on Diego Garcia has included Black Construction/Mace International JV building a 34-metre antenna facility (expected completed by April 2021) and two new 13-metre radomes (expected completed by February 2021);<ref>{{Cite web|title=Contracts for February 21, 2020|url=https://www.defense.gov/Newsroom/Contracts/Contract/Article/2091020/|access-date=15 February 2021|website=U.S. DEPARTMENT OF DEFENSE|language=en-US|archive-date=16 August 2021|archive-url=https://web.archive.org/web/20210816211358/https://www.defense.gov/Newsroom/Contracts/Contract/Article/2091020//|url-status=dead}}</ref> and SJC-BVIL moving underground the overhead power and telephone lines that run from the Navy ammunition area to the Air Force ammunition area along DG1 (expected completed by September 2022).<ref>{{Cite web|title=Contracts for July 15, 2020|url=https://www.defense.gov/Newsroom/Contracts/Contract/Article/2275570/|access-date=15 February 2021|website=U.S. DEPARTMENT OF DEFENSE|language=en-US|archive-date=16 August 2021|archive-url=https://web.archive.org/web/20210816105416/https://www.defense.gov/Newsroom/Contracts/Contract/Article/2275570//|url-status=dead}}</ref>

===Naval Support Facility Diego Garcia===
[[File:B-1 Bombers on Diego Garcia.jpg|thumb|[[Rockwell B-1 Lancer|B-1B Lancer]] bombers and [[KC-10A Extender]]s on Diego Garcia in November 2001 during the [[Afghanistan]] bombing campaign]]
[[File:US Air Force 030320-F-4338B-042 Busy bombers.jpg|thumb|[[B-2]] bomber taking off, [[B-52]] bombers & [[KC-135]] refuelers on tarmac, Diego Garcia]]

[[Naval Support Facility Diego Garcia]] provides Base Operating Services to tenant commands located on the island. The command's mission is "To provide logistic support to operational forces forward deployed to the Indian Ocean and Persian Gulf AORs in support of national policy objectives."<ref>[https://cnrj.cnic.navy.mil/Installations/NSF-Diego-Garcia/ About Navy Support Facility Diego Garcia]  retrieved 11 November 2011.</ref> KBR has run base operations support services at Naval Support Facility Diego Garcia.<ref>{{Cite web|title=Contracts for November 7, 2019|url=https://www.defense.gov/Newsroom/Contracts/Contract/Article/2011830//|access-date=15 February 2021|website=U.S. DEPARTMENT OF DEFENSE|language=en-US|archive-date=16 August 2021|archive-url=https://web.archive.org/web/20210816105823/https://www.defense.gov/Newsroom/Contracts/Contract/Article/2011830//|url-status=dead}}</ref>

===United States Air Force and Space Force units based on Diego Garcia===

*[[36th Wing|36 MSG]], [[Pacific Air Forces|Pacific Air Force]]
*Det 1, [[515th Air Mobility Operations Wing|730th Air Mobility Squadron]], [[Air Mobility Command]]
*Det 1, [[633rd Logistics Group]], [[Pacific Air Force - 1992-1994]]
*Det 1, [[21st Space Operations Squadron]], a [[Satellite Control Network]] Remote Tracking Station, [[Space Operations Command]]
*Det 2, a [[GEODSS]] facility,<ref>{{cite web |title=Ground-Based Electro-Optical Deep Space Surveillance |url=https://www.spaceforce.mil/about-us/fact-sheets/article/2197760/ground-based-electro-optical-deep-space-surveillance/ |website=United States Space Force |access-date=17 January 2026 |archive-url=https://web.archive.org/web/20250922204452/https://www.spaceforce.mil/about-us/fact-sheets/article/2197760/ground-based-electro-optical-deep-space-surveillance/ |archive-date=22 September 2025}}</ref> [[Space Operations Command]]

===United States pre-positioned vessels===
[[File:Camp Justice --Diego Garcia.jpg|thumb|upright|Camp Justice on Diego Garcia]]

The atoll shelters the ships of the United States Marine Pre-positioning Squadron Two. These ships carry equipment and supplies to support a major armed force with tanks, armoured personnel carriers, munitions, fuel, spare parts and even a mobile field hospital. This equipment was used during the [[Persian Gulf War]], when the squadron transported equipment to [[Saudi Arabia]].

The ship composition of MPSRON TWO is dynamic. During August 2010 it was composed of the following:

*[[MV Capt. Steven L. Bennett (T-AK-4296)|MV ''Capt. Steven L. Bennett'']]
*USNS ''SGT William R. Button'' (T-AK-3012),<ref>{{cite web |url=http://www.msc.navy.mil/inventory/ships.asp?ship=21 |title=USNS SGT WILLIAM R. BUTTON (T-AK 3012) |publisher=[[Military Sealift Command]] |work=Ship Inventory |access-date=27 September 2011 |date=16 January 2009 |archive-date=7 June 2011 |archive-url=https://web.archive.org/web/20110607150824/http://www.msc.navy.mil/inventory/ships.asp?ship=21 |url-status=dead }}</ref>
*MV ''SSG Edward A. Carter, Jr.'' (T-AK-4544),<ref>{{cite web |url=http://www.msc.navy.mil/inventory/ships.asp?ship=61 |title=MV SSG EDWARD A. CARTER, JR. (T-AK 4544) |publisher=[[Military Sealift Command]] |work=Ship Inventory |access-date=27 September 2011 |date=25 August 2006 |archive-date=7 June 2011 |archive-url=https://web.archive.org/web/20110607150919/http://www.msc.navy.mil/inventory/ships.asp?ship=61 |url-status=dead }}</ref>
*[[MV Maj. Bernard F. Fisher (T-AK-4396)|MV ''Maj. Bernard F. Fisher'']]
*[[USNS Lawrence H. Gianella (T-AOT-1125)|USNS ''Lawrence H. Gianella'']]
*USNS ''SGT Matej Kocak'' (T-AK-3005),<ref>{{cite web |url=http://www.msc.navy.mil/inventory/ships.asp?ship=113 |title=USNS SGT MATEJ KOCAK (T-AK 3005) |publisher=[[Military Sealift Command]] |work=Ship Inventory |access-date=27 September 2011 |date=16 January 2009 |archive-date=7 June 2011 |archive-url=https://web.archive.org/web/20110607150410/http://www.msc.navy.mil/inventory/ships.asp?ship=113 |url-status=dead }}</ref>
*USNS ''1st LT Baldomero Lopez'' (T-AK-3010),<ref>{{cite web |url=http://www.msc.navy.mil/inventory/ships.asp?ship=117 |title=USNS 1ST LT BALDOMERO LOPEZ (T-AK 3010) |publisher=[[Military Sealift Command]] |work=Ship Inventory |access-date=27 September 2011 |date=24 October 2006 |archive-date=7 June 2011 |archive-url=https://web.archive.org/web/20110607150724/http://www.msc.navy.mil/inventory/ships.asp?ship=117 |url-status=dead }}</ref>
*MV ''LTC John U. D. Page''<ref>{{cite web |url=http://www.msc.navy.mil/inventory/ships.asp?ship=134 |title=MV LTC JOHN U. D. PAGE (T-AK 4543) |publisher=[[Military Sealift Command]] |work=Ship Inventory |access-date=27 September 2011 |date=25 April 2008 |archive-date=7 June 2011 |archive-url=https://web.archive.org/web/20110607150328/http://www.msc.navy.mil/inventory/ships.asp?ship=134 |url-status=dead }}</ref>
*[[USNS GYSGT Fred W. Stockham (T-AK-3017)|USNS ''GYSGT Fred W. Stockham'']]

Five of these vessels carry supplies for the [[US Marine Corps]] sufficient to support a [[Marine Air-Ground Task Force]] for 30 days: USNS ''Button'', USNS ''Kocak'', USNS ''Lopez'', USNS ''Stockham'', and USNS ''Fisher''.

Prior to 2001, COMPSRON 2 consisted of up to 20 ships, including four Combat Force Ships which provided rapid-response delivery of equipment to ground troops in the [[United States Army]]. Three are [[lighter aboard ship]]s (LASH) which carry barges called [[Lighter (barge)|lighters]] that contain Army ammunition to be ferried ashore: MV ''American Cormorant'', SS ''Green Harbour'', (LASH), SS ''Green Valley'', (LASH), MV ''Jeb Stuart'', (LASH). There were logistics vessels to service the rapid delivery requirements of the [[United States Air Force]], [[United States Navy]] and [[Defense Logistics Agency]]. These included [[container ship]]s for Air Force munitions, missiles and spare parts; a 500-bed [[hospital ship]], and [[floating storage and offloading unit]]s assigned to [[Military Sealift Command]] supporting the Defense Logistics Agency, and an offshore petroleum discharge system (OPDS) [[Tanker (ship)|tanker]]. Examples of ships are [[MV Buffalo Soldier|MV ''Buffalo Soldier'']], MV ''Green Ridge'', pre-position tanker [[USNS Henry J. Kaiser|USNS ''Henry J. Kaiser'']], and tanker {{USNS|Potomac|T-AO-181}}.

===HF global station===
{{main|High Frequency Global Communications System}}

The United States Air Force operates a High Frequency Global Communications System transceiver site located on the south end of the atoll near the GEODSS station. The transceiver is operated remotely from [[Andrews Air Force Base]] and [[Grand Forks Air Force Base]] and is locally maintained by NCTS FE personnel.<ref>{{cite web|url=https://www.numbers-stations.com/military/usa/hfgcs/|title=The HF-GCS and Emergency Action Messages|website=www.numbers-stations.com|date=8 February 2016 |access-date=20 May 2020}}</ref><ref>{{cite web|url=http://www.udxf.nl/USAF-HFGCS.pdf |archive-url=https://web.archive.org/web/20170326204149/http://udxf.nl/USAF-HFGCS.pdf |archive-date=26 March 2017 |url-status=live|title=USAF High Frequency Global Communications System|website=www.udxf.nl|date=28 February 2016|access-date=20 May 2020}}</ref>

===Naval Computer and Telecommunications Station Far East Detachment Diego Garcia===
Naval Computer and Telecommunications Station Far East Detachment Diego Garcia operates a detachment in Diego Garcia. This detachment provides base telephone communications, base network services (Local Network Services Center), pier connectivity services, and an AN/GSC-39C [[Super high frequency|SHF]] satellite terminal, operates the [[Air Force Technical Applications Center|Hydroacoustic Data Acquisition System]], and performs on-site maintenance for the remotely operated Air Force [[HF-GCS]] terminal.{{citation needed|date=April 2012}}

In July 2023, Reuters confirmed an underwater fibre-optic cable spur from the [[Oman Australia Cable]] had been constructed to Diego Garcia during 2022.<ref>{{cite news |last1=Brock |first1=Joe |title=Inside the subsea cable firm secretly helping America take on China |url=https://www.reuters.com/investigates/special-report/us-china-tech-subcom/ |website=Reuters |date=6 July 2023 |access-date=7 July 2023 |archive-date=4 December 2023 |archive-url=https://web.archive.org/web/20231204061949/https://www.reuters.com/investigates/special-report/us-china-tech-subcom/ |url-status=live }}</ref>

===Naval Security Group Detachment Diego Garcia===
[[Naval Security Group]] detachment Diego Garcia was disestablished on 30 September 2005.<ref>OPNAVNOTE 5450 dated 6 September 2005.</ref> Remaining essential operations were transferred to a contractor. The large AN/AX-16 High Frequency [[Radio direction finding]] [[Circularly Disposed Antenna Array]] has been demolished, but the four satellite antenna [[radome]]s around the site remain {{As of|2010|lc=y}}.{{citation needed|date=April 2012}} However, multiple CDAAs on the island still exist, as seen in satellite imagery.

===Space Shuttle===
The island was designated as one of the [[Space Shuttle abort modes|emergency landing]] [[list of Space Shuttle landing sites|sites worldwide]] for the [[NASA]] [[Space Shuttle]].<ref>{{Cite web |last=Marsh |first=Jenni |date=9 March 2019 |title=Is the United States about to lose control of its secretive Diego Garcia military base? |url=https://www.cnn.com/2019/03/09/asia/chagos-islands-feature-intl/index.html |access-date=27 October 2023 |website=CNN |language=en |archive-date=27 October 2023 |archive-url=https://web.archive.org/web/20231027151858/https://www.cnn.com/2019/03/09/asia/chagos-islands-feature-intl/index.html |url-status=live }}</ref><ref>{{Cite web |last=Office |first=U. S. Government Accountability |title=Space Shuttle: Readiness of the Transoceanic Abort Landing Sites {{!}} U.S. GAO |url=https://www.gao.gov/products/nsiad-89-22 |access-date=27 October 2023 |website=www.gao.gov |language=en |archive-date=27 October 2023 |archive-url=https://web.archive.org/web/20231027151909/https://www.gao.gov/products/nsiad-89-22 |url-status=live }}</ref> None of these facilities were ever used throughout the life of the shuttle program.

==Cargo service==
[[File:Mv-baffin-strait-route.png|thumb|right|From 2004 to 2009, [[MV Baffin Strait (T-AK W9519)|MV ''Baffin Strait'']] transited between Singapore and Diego Garcia once a month.]]

All consumable food and equipment are brought to Diego Garcia by sea or air, and all non-biodegradable waste is shipped off the island as well. From 1971 to 1973, United States Navy LSTs provided this service. Beginning in 1973, civilian ships were contracted to provide these services. From 2004 to 2009, the U.S.-flagged [[container ship]] [[MV Baffin Strait (T-AK W9519)|MV ''Baffin Strait'']], often referred to as the "DGAR shuttle", delivered 250 containers every month from Singapore to Diego Garcia.<ref name="dgar">{{cite web|url=http://www.msc.navy.mil/N00p/pressrel/press07/press51.htm |title=Change at the helm for MSC's Diego Garcia office |publisher=Msc.navy.mil |date=8 November 2007 |access-date=21 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20110806085739/http://www.msc.navy.mil/N00p/pressrel/press07/press51.htm |archive-date=6 August 2011 }}</ref> The ship delivered "more than 200,000 tons of cargo to the island each year".<ref name="dgar"/> On the return trip to Singapore, it carried recyclable metals.<ref>{{cite web|url=http://deparc.xservices.com/pdfs/stories/Navy/FY06_SW_Success_Stories.pdf |title=2006 Pollution Prevention and Solid Waste Success Stories |access-date=18 March 2008 |author=Commander, Navy Installations Command (CNIC) |year=2007 |publisher=US Department of the Navy}}{{dead link|date=April 2017|bot=medic}}{{cbignore|bot=medic}}</ref>

In 2004, [[TransAtlantic Lines]] outbid [[Sealift Incorporated]] for the transport contract between Singapore and Diego Garcia.<ref name="sag">{{cite web|url=http://www.amo-union.org/newspaper/Morgue/11-2004/Sections/News/sagamore.htm |title=Non-union operator wins charter held by Sagamore |access-date=26 September 2007 |author1=American Maritime Officers |date=November 2004 |work=AMO Currents |publisher=American Maritime Officers Union |url-status=dead |archive-url=https://web.archive.org/web/20060720230429/http://www.amo-union.org/Newspaper/Morgue/11-2004/Sections/news/sagamore.htm |archive-date=20 July 2006 }}</ref> The route had previously been serviced by Sealift Inc.'s ''MV Sagamore'', crewed by members of [[American Maritime Officers]] and [[Seafarers' International Union]].<ref name="sag"/> TransAtlantic Lines reportedly won the contract by approximately 10 percent, representing a price difference of about $2.7 million.<ref name="sag"/> The ''Baffin Straits'' charter ran from 10 January 2005, to 30 September 2008, at a daily rate of $12,550.

==See also==
*[[James Horsburgh]]
*[[List of British Army installations]]
*[[List of United States military bases]]
*[[Robert Moresby]]
*''[[Stealing a Nation]]''

==References==
{{Reflist}}

==Bibliography==
{{refbegin|30em}}
*{{cite book |last=Edis|first= Richard |title=Peak of Limuria: the Story of Diego Garcia and the Chagos Archipelago |location=Chippenham, UK |publisher=Antony Rowe Ltd |year=2004 |ref=Edis}}
*{{cite web |url=http://www.reefnewmedia.co.uk/cmt_chagos/uploads/Chagos-Flora-Checklist_190809.pdf |title=British Indian Ocean Territory Plant Species Checklist |last=Hamilton |first=Martin |author2=John Topp |date=19 August 2009 |publisher=[[Royal Botanic Gardens, Kew]] & Chagos Conservation Trust |access-date=27 September 2011 |ref=Hamilton |archive-url=https://web.archive.org/web/20111202110352/http://www.reefnewmedia.co.uk/cmt_chagos/uploads/Chagos-Flora-Checklist_190809.pdf |archive-date=2 December 2011 |url-status=dead }}
*{{cite book |author1=Ladwig III |author2=Walter C. |author3=Andrew S. Erickson |author4=Justin D. Mikolay |title=Diego Garcia and American Security in the Indian Ocean |series=in Carnes Lord and Andrew Erickson Rebalancing US Forces: Basing and Forward Presence in the Asia Pacific |location=Annapolis, MD |publisher=Naval Institute Press |year=2014 |url=https://books.google.com/books?id=ntD3AgAAQBAJ&pg=PT92 |ref=Ladwig |isbn=978-1-61251-464-2}}
*{{cite book |url=http://www.zianet.com/tedmorris/dg/nrmp.html |title=Diego Garcia Integrated Natural Resources Management Plan |publisher=US Naval Support Facility Diego Garcia |date=September 2005 |ref=NRMP |archive-date=4 April 2023 |access-date=1 January 2011 |archive-url=https://web.archive.org/web/20230404193643/http://www.zianet.com/tedmorris/dg/nrmp.html |url-status=live }}
*{{cite book |last=Sand|first= Peter H. |year=2009 |title=United States and Britain in Diego Garcia&nbsp;– the Future of a Controversial Base |publisher=Palgrave Macmillan |location=New York |isbn=978-0-230-61709-4 |ref=Sand}}
*{{cite book |editor-last=Sheppard|editor-first= Charles R. C. |editor2=M. R. D. Seaward |year=1999 |title=Ecology of the Chagos Archipelago |volume= 2 |series=Linnean Society Occasional Publications |publisher=Westbury for the [[Linnean Society of London]] |isbn=1-84103-003-1 |ref=Sheppard_Seaward}}
*{{cite book |url=http://www.zianet.com/tedmorris/dg/chagos_conservation_management_plan_2003.pdf |archive-url=https://web.archive.org/web/20110311194003/http://www.zianet.com/tedmorris/dg/chagos_conservation_management_plan_2003.pdf |archive-date=11 March 2011 |url-status=live |title=Chagos Conservation Management Plan |last=Sheppard |first=Charles |author2=Mark Spalding |publisher=British Indian Ocean Territory Administration, [[Foreign and Commonwealth Office]] |location=London |year=2003 |ref=Sheppard_Spalding }}
*{{cite book |editor-last=Stoddart |editor-first=D. R. |editor2=J. D. Taylor |year=1971 |title=Geography and ecology of Diego Garcia Atoll, Chagos Archipelago |series=Atoll Research Bulletin |volume=149 |publisher=[[Smithsonian Institution]] |location=Washington, DC |url=http://www.sil.si.edu/digitalcollections/atollresearchbulletin/issues/00149x.pdf |archive-url=https://web.archive.org/web/20110311194002/http://www.sil.si.edu/digitalcollections/atollresearchbulletin/issues/00149x.pdf |archive-date=11 March 2011 |url-status=live |ref=Stoddart }}
*{{cite book |last=Topp |first=J. M. W. |year=1988 |title=An Annotated Check List of the Flora of Diego Garcia, British Ocean Territory |series=Atoll Research Bulletin |volume=313 |location=Washington D.C. |publisher=[[Smithsonian Institution]] |url=http://www.zianet.com/tedmorris/dg/atoll_research_bulletin_313_flora_of_diego_garcia_1988.pdf |archive-url=https://web.archive.org/web/20110311194050/http://www.zianet.com/tedmorris/dg/atoll_research_bulletin_313_flora_of_diego_garcia_1988.pdf |archive-date=11 March 2011 |url-status=live |ref=Topp }}
*{{cite journal |last=Urish |first=Daniel |year=1974 |title=Fresh water on the coral atoll island |journal=The Military Engineer |volume=429 |pages=25–27 |url=http://www.zianet.com/tedmorris/dg/urish1974.pdf |archive-url=https://web.archive.org/web/20110311194031/http://www.zianet.com/tedmorris/dg/urish1974.pdf |archive-date=11 March 2011 |url-status=live |ref=Urish }}
*{{cite book |editor-last=Vacher|editor-first= H. Leonard |editor2=Terrench Quinn |title=Geology and Hydrogeology of Carbonate Islands |series=Developments in Sedimentology |year=1964 |volume=54 |publisher=[[Elsevier]] |oclc=1353476412 |ref=Vacher}}
{{refend}}

==Further reading==
{{Library resources box}}

*{{cite book |last=Hutson|first= A. M. |year=1975 |title=Observations on the Birds of Diego Garcia, Chagos Archipelago, with Notes on Other Vertebrates |series=Atoll Research Bulletin |volume=175 |location=Washington D.C. |publisher=[[Smithsonian Institution]] |url=http://www.zianet.com/tedmorris/dg/atoll_research_bulletin_175_birds_of_diego_garcia_1975.pdf |archive-url=https://web.archive.org/web/20110311194114/http://www.zianet.com/tedmorris/dg/atoll_research_bulletin_175_birds_of_diego_garcia_1975.pdf |archive-date=11 March 2011 |url-status=live }}
*Pilger, John, ''Freedom Next Time'' (2007).
*Urish, Daniel W., ''Coral, Copra, and Concrete: An Illustrated Memoir of Diego Garcia Atoll'' (2015).
*Wenban-Smith, N. and Carter, M., ''Chagos: A History, Exploration, Exploitation, Expulsion'' Published by Chagos Conservation Trust, London (2016).
*Winchester, Simon, ''Outposts: Journeys to the Surviving Relics of the British Empire'' (2004).

==External links==
{{External links|date=January 2026}}
{{Commons category}}
{{Americana Poster}}
*[https://www.gov.uk/government/publications/ukmauritius-agreement-concerning-the-chagos-archipelago-including-diego-garcia-cs-mauritius-no12025 UK/Mauritius: Agreement concerning the Chagos Archipelago including Diego Garcia]
*[https://web.archive.org/web/20120422112040/http://www.chagos.org/home.htm Chagos Islands Indigenous Population Support Internet Site]
*[https://news.bbc.co.uk/2/hi/uk_news/england/7075361.stm BBC News Exiles lose appeal over benefits] 02/11/07
*[[Jonathan Freedland]], [http://www.nybooks.com/articles/22691 "A Black and Disgraceful Site"], ''[[The New York Review of Books]]'', 28 May 2009.
*Erickson, Andrew S., Walter C. Ladwig III and Justin D. Mikolay,[https://web.archive.org/web/20121003051516/http://users.ox.ac.uk/~mert1769/Diego%20Garcia.pdf "Diego Garcia and the United States' Emerging Indian Ocean Strategy,"] ''Asian Security,'' Vol. 6, No. 3 (Autumn 2010), pp.&nbsp;214–237.
*[http://www.diegogarciaonline.com/ Diego Garcia Online: Information for locals of Diego Garcia.] {{Webarchive|url=https://web.archive.org/web/20190714193308/http://www.diegogarciaonline.com/ |date=14 July 2019 }}
*[http://sgs.lpi.org.uk/seagreensingers/theisland Recording of ''The Island''] {{Webarchive|url=https://web.archive.org/web/20101209151500/http://sgs.lpi.org.uk/seagreensingers/theisland/ |date=9 December 2010}}, a jazz opera broadcast on radio in the 1960s about Garcia Diego written by [[William Russo (musician)|William Russo]] and [[Adrian Mitchell]], performed by [[Cleo Laine]] and [[Denis Quilley]] and Russo Orchestra.
*[http://www.law.northwestern.edu/journals/jihr/v5/n1/4/Nauvel.pdf "A Return from Exile in Sight? The Chagossians & their Struggle"] {{Webarchive|url=https://web.archive.org/web/20110302222704/http://www.law.northwestern.edu/journals/jihr/v5/n1/4/Nauvel.pdf |date=2 March 2011 }}, from the ''Northwestern Journal of International Human Rights''
*[https://web.archive.org/web/20101230022139/http://www.historycommons.org/timeline.jsp?timeline=diego_garcia Diego Garcia] Timeline of Diego Garcian History, 1770–2008, posted the History Commons
*[https://web.archive.org/web/20120716181503/http://homepage.ntlworld.com/jksonc/docs/bancoult-d16b1.html US/UK BIOT defence agreements, 1966–1982], US court filing

{{Chagos Islands dispute}}
{{Atolls of the Chagos Archipelago}}
{{List of British Territories capitals}}
{{Highest points of Asia}}
{{Authority control}}

[[Category:Atolls of the Chagos Archipelago]]
[[Category:Capital cities in Asia]]
[[Category:Capital cities of dependent territories of the United Kingdom]]
[[Category:Geography of the British Indian Ocean Territory]]
[[Category:Islands of the British Indian Ocean Territory]]
[[Category:Mauritius–United Kingdom relations]]
[[Category:Mauritius–United States relations]]
[[Category:Military of the British Forces British Indian Ocean Territories]]
[[Category:Ramsar sites in dependent territories of the United Kingdom]]
[[Category:United Kingdom–United States relations]]
[[Category:Prison islands]]