All events · Empires Unmade

Depopulation of the Chagos Archipelago

1968–1973 · South & Central Asia

Displacement Territory Seized

Displaced

1,800

approximately 1,500–2,000 Chagossians were forcibly removed and relocated mainly to Mauritius and Seychelles

Share of the population affected

100%

of the resident population of the Chagos Archipelago before its depopulation, including those prevented from returning while abroad, 1966

Territory

60 km²

The Chagos Archipelago (British Indian Ocean Territory), including Diego Garcia, detached by the UK from Mauritius in 1965 ahead of Mauritian independence

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What happened

In 1965, the United Kingdom detached the Chagos Archipelago from the colony of Mauritius, three years before Mauritian independence, to create the British Indian Ocean Territory (BIOT). Between 1968 and 1973, the UK forcibly removed the archipelago's entire population of roughly 1,500–2,000 Chagossians, relocating them mainly to Mauritius and Seychelles under harsh conditions, to allow the United States to build a military base on Diego Garcia, which remains operational. The International Court of Justice issued an advisory opinion in 2019 finding that the UK's detachment of Chagos was unlawful and that decolonization of Mauritius had not been lawfully completed. In 2025, the UK and Mauritius concluded a treaty under which the UK will cede sovereignty of the archipelago to Mauritius while retaining a long-term lease on Diego Garcia for the joint UK-US base; Chagossians themselves were not direct parties to those negotiations and continue to press for a right of return and fuller compensation.

Parties

The United Kingdom, having detached the Chagos Archipelago from Mauritius to form the British Indian Ocean Territory, forcibly removed the entire Chagossian population to enable a US military base on Diego Garcia

Disputed

The UK and US justified the removals on national security grounds tied to the Diego Garcia base; the ICJ's 2019 advisory opinion and a UN General Assembly resolution found the UK's continued administration unlawful, though the UK disputed the opinion's binding effect until agreeing to cede sovereignty in the 2025 treaty; Chagossian groups say their exclusion from the UK-Mauritius negotiations and unresolved questions about a right of return and compensation remain unaddressed.

The denominator

British and Mauritian records of the 1960s put the archipelago's population at roughly 1,000 on Diego Garcia and several hundred more on Peros Banhos and the Salomon islands; estimates of the total Chagossian community removed or barred from return run from about 1,400 to 2,000. The entire population was removed, so the affected figure and the baseline are close to identical by construction.

Where the baseline comes from

On the death toll

Both fields are null because the removal of roughly 1,500-2,000 Chagossians between 1968 and 1973 was carried out without killing. Chagossian testimony and UK litigation record destitution, illness and suicides among those deposited in Mauritius and the Seychelles — the condition Chagossians call sagren — but no court, commission or study has produced a mortality figure.

Documented forms of violence

Destruction of Property

UK High Court judgments in the Bancoult litigation and the record before the ICJ document the clearance of the plantation settlements, the abandonment or destruction of islanders' homes and possessions and the killing of their animals during the removal.

Formal findings

ICJ (2019) — Advisory opinion on the Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965: the detachment was not based on the free and genuine expression of the will of the people concerned, Mauritius's decolonisation was not lawfully completed, the UK's continued administration is a wrongful act, and it must end that administration as rapidly as possible; the Court referred the resettlement of Chagossians to the General Assembly — source