a river on the island of Sumatra, Indonesia. It measures about 500 km long and drains an area of about 57,000 sq km. It rises in the Barisan Mountains. In its middle and lower reaches, the Musi intersects a marshy low-lying plain. As it empties into the Bangka Strait, the Musi forms a delta. Its source is rainwater; water is abundant throughout the year. The Musi is generally navigable to 360 km from its mouth; sea vessels, however, are too large to sail more than 85 km upstream, and thus cannot go beyond Palembang. The plain drained by the Musi River is one of Sumatra’s important agricultural regions.