Sulawesi (sōō´läwā´sē), formerly Celebes (sĕl´əbēz), island (1990 pop. 12,511,163), c.73,000 sq mi (189,070 sq km), largest island in E Indonesia, E of Borneo, from which it is separated by the Makasar Strait. Extremely irregular in shape, it comprises four large peninsulas separated by three gulfs—Tomini on the northeast, Tolo on the southeast, and Bone on the south. Ujung Pandang (Makasar) is its chief city and port; other important towns are Manado, Gorontalo, and Palopo.
The terrain is almost wholly mountainous, with many active volcanoes. Mt. Rantemario (11,286 ft/3,440 m) and Mt. Rantekombola (11,335 ft/3,455 m) are the highest peaks. There are numerous lakes; Towuti is the largest and Tondano, with its waterfall, the most beautiful. Asian and Australian elements are comingled in the fauna, which includes the babirusa (resembling swine), the anoa, a small wild ox found only in Sulawesi, the baboon, some rare species of parrot, and many crocodiles.
Valuable stands of timber cover much of the island; many forest products are exported. Mineral resources include nickel, gold, diamonds, sulfur, and low-grade iron ore. The mountainous terrain, with only a few narrow coastal plains, limits agriculture; many inhabitants seek their livelihood from the sea, and there are trepang (sea cucumber) and mother-of-pearl industries. Sulawesi is, however, a major source of copra, and corn, rice, cassava, yams, tobacco, and spices are grown. Tourism was developed in the 1990s, and Sulawesi has become especially attractive to divers.
The inhabitants of Sulawesi are Malayan, except for some indigenous ethnic groups in the interior. The largest ethnic group is the Makasarese-Bugis, who are renowned as seafaring traders; they are Muslim. In the north are the Minahassa, who are Christian. The Univ. of North and Central Sulawesi is in Manado, and private universities are in Manado, Gorontalo, and Ujung Pandang.
Human settlement of the island is ancient. Paleolithic art found in Sulawesi caves has been dated to at least 40,000 years ago. The Portuguese first visited the island in 1512. The Dutch expelled the Portuguese in the 1600s and conquered the natives in the Makasar War (1666–69). In 1950, it became one of 10 provinces of newly created Indonesia; it has since been divided into 4 provinces. Since 1998 the island has been the site of violence between Muslims and Christians. The Sulawesi Sea or Celebes Sea is north of the island, between it and the Philippines.