Indochina, Fr. Indochine, former federation of states, SE Asia. It comprised the French colony of Cochin China and the French protectorates of Tonkin, Annam, Laos, and Cambodia (Cochin China, Tonkin, and Annam were later united to form Vietnam). The capital was Hanoi. The federation formed the easternmost region of the Indochinese peninsula (which it shared with Myanmar, Thailand, and Malaya) and faced E on the South China Sea. The cultures of Indochina were influenced by China and India. The centuries before European intervention saw the growth and decline of the Khmer Empire in Cambodia, the rise and fall of Champa, and the steady expansion of Annam. European penetration began in the 16th cent.; in the 19th-century race for a colonial empire, the French took (1862, 1867) Cochin China as a colony and gained protectorates over Cambodia (1863), Annam (1884), and Tonkin (1884). In 1887 they formed those four states into a union of Indochina, with a governor-general at its head; Laos was added to the union in 1893. In World War II, France was forced to accept Japanese intervention in N Indochina in 1940; the subsequent Japanese move into S Indochina (July, 1941) was viewed by the United States as a threat to the Philippines; it prompted the freezing of all Japanese assets in the United States and precipitated the diplomatic exchanges cut short by the Japanese attack on Pearl Harbor. Even before the end of the war, the French announced plans for a federation of Indochina within the French Union, with greater self-government for the various states. The federation was accepted in Cambodia and Laos. Vietnamese nationalists, however, demanded (1945) the complete independence of Annam, Tonkin, and Cochin China as Vietnam, and after Dec., 1946, these regions were plunged into bitter fighting between the French and the extreme nationalists, oftentimes led by Communists. The war in Vietnam dragged on for years, culminating in the French defeat at Dienbienphu. The Geneva Conference in 1954 effectively ended French control of Indochina.