Borneo is a large island of south east Asia, lying to the east of the Malaysian peninsula. It is bounded by the South China Sea, the Java Sea, the Macassar Strait, the Celebes Sea and the Sulu Sea. With a land area of 287,863 square miles (745,561 km2) it is the third largest island in the world (after Greenland and New Guinea).
Politically, Borneo is divided between three nations. By far the largest part of the island (Kalimantan) forms part of Indonesia. Parts of the north of the island, known as Sarawak and Sabah, belong to Malaysia. Small enclaves within the Malaysian section form the independent and oil-rich Sultanate of Brunei.
Much of the island is mountainous and covered by jungle or rain forest. It is home to numerous indigenous peoples, many of whom have had only very limited contact with the outside world.