Celebes Sea, Indonesian Laut Sulawesi, sea of the western Pacific Ocean, bordered on the north by the Sulu Archipelago and Sea and Mindanao Island, on the east by the Sangi Islands chain, on the south by Celebes (Sulawesi), and on the west by Borneo. It extends 420 miles (675 km) north-south by 520 miles (837 km) east-west and occupies a total surface area of 110,000 square miles (280,000 square km). The sea, opening southwest through the Makassar Strait to the Java Sea, fills a steep-sided, generally flat-bottomed basin formed by downfaulting of a tectonic block. Over half of its area is more than 13,000 feet (4,000 m) deep, the greatest recorded depth being 20,406 feet (6,220 m). The edges of this enclosed basin are visible in the line of volcanic cones in northern Celebes and the Sang Islands and the mountains of the Sulu Archipelago and Mindanao. Deep water enters the sea from the Pacific south of Mindanao, flowing southwest to leave by the Makassar Strait. This pattern also holds true for surface currents.
Although the Dutch seized parts of Celebes and the Sang group early in the 17th century, the sea itself was long dominated by traders and pirates from Borneo and the surrounding islands. It did not come under colonial control until late in the 19th century. Fishing is important, and there is much coastal and interisland trade.