The Brahmaputra River is one of the largest rivers in the world. It originates in southwestern Tibet as the Yarlung River. It flows across southern Tibet where it is known as Dihang. Then it breaks through the Himalayas in great gorge, approximately at 31°30īN and 82°0īE. Its basin covers the areas of Tibet, China, India and Bangladesh. It has a long course through the dry and flat region of southern Tibet before it breaks through the Himalayas.

The chief tributaries of the Brahmaputra River are the Amochu, Raidak, Sankosh, Mans, Bhareli, Dibang and Luhit. The total length of the river from its source in southwestern Tibet to the mouth in the Bay of Bengal is about 2,850 km. Within the Bangladesh territory, Brahmaputra-Jamuna is 276 km long, of which Brahmaputra is only 69 km. It has a long course through the dry and flat region of southern Tibet before it breaks through the Himalayas near the Namcha Barwa peak at about 7,755m. Its chief tributaries in India are the Amochu, Raidak, Sankosh, Mans, Bhareli, Dibang and Luhit. The course of the Brahmaputra in Tibet is known as the Tsang-po. Here the river flows through the plain, which is south of Lhasa. The flow of the river here is sluggish.

In Assam the river flows southwest to a point north of the Shillong Massif before entering Bangladesh. The Brahmaputra is known as the Dihang in Assam. In the plains of Assam the Brahmaputra River is very mighty and spreads into a vast expanse of water. The catchment of this mighty river is about 5,83,000 sq km of which about 47,000 sq km lies in Bangladesh. After traversing through the Assam valley, it sweeps round the Garo Hills, and enters Bangladesh and flows southward joining the Ganges. During the monsoon, the river discharges a large amount of water as well as sediments. The width of the river varies from 3 km to 18 km but the average width is about 10 km. The width/depth ratios for individual channels of the Brahmaputra vary from 50:1 to 500:1.

Most of the Indian and Bangladeshi rivers bear female names, this river has a rare male name, as it means `son of Brahma` in Sanskrit. The lower reaches of the river are sacred for the Hindus.