Irawadi, Or Airavati Irrawaddy (" great river," or "elephantine river"), the principal stream in India E. of the Brahmapootra. It rises on the confines of Thibet and Burmah, at the E. extremity of the Snowy range of the Himalaya, about lat. 28° N., Ion. 98° E., flows S. across the territory of Burmah, which it divides into two nearly equal parts, and traverses the state of Pegu in British Burmah, entering the bay of Bengal and the gulf of Martaban by several mouths which form an extensive delta. Its whole length is 1,060 m. It separates 140 m. below the S. frontier of Burmah into two branches, the eastern of which is named the Rangoon or Siriam from the principal cities on its banks, and falls into the gulf of Martaban, while the western, called the Bassein, enters the bay of Bengal near Cape Negrais. The delta is formed by numerous offsets from both these branches. The Irrawaddy has two striking deviations from its general southerly course: one just below the mouth of the Tapan, about lat. 24° 15', where it makes a bold curve in the shape of the letter S; and the other at Amarapura, where it turns sharply W., and, after receiving the waters of its largest tributary, the Khyen-Dwen, flows successively S., S. W., and again S. The principal cities and towns on its banks are Bhamo (a trading town having a considerable traffic with China), Amarapura and Ava, former capitals, Mandelay, the present capital of Burmah, Pagan, Maloon, Prome, Bassein, and Rangoon. From above the junction of the Khyen-Dwen to Maloon the Irrawaddy spreads itself over a channel reaching during the inundation from June to September to a width of 4 or 5 m.

It is then restricted between steep and hilly banks, and does not expand again considerably until it has passed Prome. It is navigable to Ava at all seasons by boats drawing 3 ft. of water, and during the rains vessels of 200 tons can ascend to Bhamo, a distance of 800 m. from the sea. Two steam navigation companies run steamers on the Irrawaddy, making 60 trips a year. Klaproth and the Chinese geographers consider the Irrawaddy a continuation of the Sanpo of Thibet; but the latter river is now generally admitted, though not positively ascertained, to be identical with the Brahmapootra.