Bali, island, southern Indonesia, one of the Lesser Sunda Islands, in the Indian Ocean. It is situated between the island of Java to the west, from which it is separated by Bali Strait, and the island of Lombok to the east from which it is separated by Lombok Strait. Bali is 145 km (90 mi) long and 80 km (50 mi) wide.

The principal cities are the northern port of Singaraja and Denpasar, the capital, near the southern coast. Mountain ranges cross the island from east to west. The highest point on the island is Mount Agung (3,142 m/10,308 ft), a volcano that erupted in March 1963. In the south the land descends to form an alluvial plain, watered by shallow rivers, dry in the dry season and overflowing whenever there are periods of heavy rains.