Irrawaddy, the chief river of Burma. The Irrawaddy is about 1,300 miles (2,100 km) long. It is formed in the mountains of northern Burma where the Mali and Nmai rivers join. The Irrawaddy flows southward, except for two major bends to the west. Below Mandalay it receives the Chindwin, its main tributary, and widens to as much as four miles (6.4 km). In the delta, which begins about 140 miles (225 km) inland, the river branches into many arms and flows across one of the richest rice-producing areas in the world. It empties into the Andaman Sea, part of the Indian Ocean.

The Irrawaddy is one of Burma's chief transportation routes. Most of Burma's people live along the river valley, where a large surplus of rice is grown and exported. Rangoon, Burma's capital, is connected by a canal to the eastern arm of the delta.