Indochina, or Indochinese Peninsula, the southeast peninsula of Asia. Politically it includes Vietnam (the former states of Tonkin, Annam, and Cochin China), Laos, Cambodia, Thailand (formerly known as Siam), Malaya (part of Malaysia), Singapore, and Burma. In the first half of the 20th century “Indochina” referred to French Indochina, the area east and south of Siam, consisting of Vietnam, Laos, and Cambodia.
The peninsula is bounded on the north by India and China, on the east and south by the South China Sea and Gulf of Thailand, and on the west by the Andaman Sea and Bay of Bengal. Much of the area is mountainous, and the rivers are largely unnavigable. The peninsula has a tropical climate with heavy seasonal rainfall. Major crops are rice and rubber.
Toward the east coast of the peninsula is a rugged north-south mountain chain. Tonkin and Annam, the countries east of the mountains, fell under the domination of China in the second century B.C. With the exception of occasional periods of independence, the area remained under Chinese overlordship for 2,000 years. Annam began expanding in the 15th century and gradually absorbed all the east coastal area of the peninsula.
West of the mountains, the great commercial kingdom of Funan dominated the region from the first to the sixth century A.D. The Khmers (Cambodians), a native people, became strong around the ninth century and created a powerful empire that dominated Indochina. ( .) The Khmer Empire was reduced to a small kingdom by the early 1400's, in part by the Thais, a northern people who had migrated south. The Thais established the kingdom of Ayudhya. They also spread into Burma, where they were called Shans.
In 1547 Burma invaded Ayudhya and for the next 200 years both kingdoms were continuously at war. The Burmese finally destroyed Ayudhya in 1767. The Thais, however, quickly drove out the Burmese and reestablished their kingdom, which came to be known as Siam.
The earliest European traders were the Portuguese, who seized Malacca on the Malay Peninsula in 1511. Within the century commercial supremacy passed to the Dutch, and during the Napoleonic Wars to the British, who founded the city of Singapore in 1819. In the late 19th century Burma and the Malay Peninsula became part of the British Empire. Siam remained independent.
In the meantime the French had gained great influence to the east. In the early 19th century they assisted an Annamese emperor to gain control over Tonkin, Annam, and Cochin China. By 1884, however, the French had taken control of these areas and of Cambodia as well. In 1887 the areas were organized into the Indochinese Union (French Indochina). By 1904 the French by piecemeal conquest had added Laos to the union.
The peninsula was occupied by Japan during World War II. Following the war Burma, Malaya, and Singapore were granted independence by Britain; Cambodia, Laos, and Vietnam, by France. For further history, see the articles on these countries.