large island of Indonesia, just south of the Malay Peninsula: 183,970 sq mi (476,480 sq km); pop. (with small nearby islands) 36,506,000
An island of western Indonesia in the Indian Ocean south of the Malay Peninsula. Long an important stopping point on the trading route between China and India, the island came under Dutch control in the 1600s, becoming part of the Dutch East Indies in 1800. Sumatra joined newly independent Indonesia in 1949.