British Indian Ocean Territory, archipelago, c.1,180 mi (1,900 km), NE of Mauritius, in the central Indian Ocean. The more than 50 islands, which form the Chagos Archipelago and are located on the southern end of a chain of sea mounts that also includes Lakshadweep and the Maldives, were administered by Mauritius before they were made a separate dependency by the British in 1965. Their importance is primarily strategic; the United States and Britain maintain a major naval facility on the main island, Diego Garcia. Between 1967 and 1973 Britain evicted the Chagos islanders as the archipelago was converted to purely military use; a case brought in 1975 by islanders led to a settlement and compensation in 1982. In 2000, however, islanders secured a British court decision declaring their explusion illegal, but the British government subsequently (2004) prevented their return to the outlying Chagos islands. Islanders again successfully challenged the government in court in 2007, but the government won on appeal the following year (on the basis of the 1982 settlement), and that decision was upheld by the European Court of Human Rights in 2012. In 2010 the British government established one of the world's largest marine reserves (210,000 sq mi/545,000 sq km) in the waters surrounding the islands. The archipelago is claimed by Mauritius, Maldives, and Seychelles.