Between 1967 and 1973, the indigenous people of the Indian Ocean's Chagos Archipelago were forcibly displaced from their homelands so the US Government could construct a strategic military base on the island of Diego Garcia. The people of Diego Garcia and the rest of the Chagos Archipelago now live in poverty in the island nations of Mauritius and Seychelles, nearly 2,000 kilometres from their homes. Analysing formerly classified government documents, this paper demonstrates how between the end of World War II and the final removals in 1973, the US Government planned, ordered, financed, helped orchestrate, and participated in the expulsion of the exiled people, known as Chagossians or Ilois. While some have detailed the role the British Government played in the removals, this paper clarifies how the US Government bears primary responsibility for the expulsion. Ultimately the creation of the base at Diego Garcia and the expulsion of the Chagossians reveal much about how the United States has exercised its political, economic, and military will on the world since World War II. The paper explains the significance of Diego Garcia and the expulsion of the Chagossians to post-war US foreign relations, incorporating comparative analyses of other forced migrations caused by the construction of US military facilities, including those in the Marshall Islands; Thule, Greenland; Okinawa, Japan; and Vieques, Puerto Rico.