Brahmaputra flows some 2,900 kilometres from its source (Manasarovar Lake region, near Mount Kailash, on the northern side of the Himalayas in Tibet) to its confluence with River Ganges. It flows along southern Tibet to break through the Himalayas and then into Arunachal Pradesh (India). It flows through the Assam Valley as Brahmaputra and in the south through Bangladesh as the Jamuna River (not to be mistaken with Yamuna of India). In the Ganges Delta, it merges with the Padma, the name of the Ganges river in Bangladesh, and after merging with Padma, it becomes Meghna, before emptying into the Bay of Bengal.

Course of Brahmaputra River in Tibet
The Brahmaputra river course in Tibet signifies its origin or the upper course. The Yarlung Tsangpo or Brahmaputra River originates in the Jima Yangzong glacier near Mount Kailash in the northern Himalayas. It then flows east for about 1700 km, at an average height of 4000 m, and is thus the highest of the major rivers in the world. From its source, the river runs for nearly 1,100km in an easterly direction between the main range of the Himalayas to the south and the Kailash Range to the north. At its easternmost point, the river bends around Mt. Namcha Barwa, and forms the Yarlung Tsangpo Canyon, which is considered the deepest in the world. During that stretch, the river enters northern Arunachal Pradesh state in India, where it is known as the Dihang or Siang River.

Course of Brahmaputra River in India
River Brahmaputra in India starts from the Arunachal Pradesh. The river enters Arunachal Pradesh and is called Siang and makes a very rapid descend from its original height in Tibet, and finally appears in the plains, where it is called Dihang. It flows for about 35 km and is joined by two other major rivers like Dibang and Lohit. From this point of convergence, the river becomes very wide and is called Brahmaputra. it then enters the state of Assam, and becomes wider. The Jia Bhoreli joins the river in Sonitpur District. At this joint, the river is known as the Kameng River. This river flows across the entire stretch of Assam.

Between the districts of Dibrugarh and Lakhimpur, the river gets divided into two channels; the northern Kherkutia channel and the southern Brahmaputra channel. The two channels join again at about 100 km downstream forming the Majuli Island. At Guwahati near the ancient pilgrimage centre of Hajo, the Brahmaputra penetrates through the rocks of the Shillong Plateau, and is at its narrowest at 1 km bank-to-bank. Because the Brahmaputra River is the narrowest at this point, the Battle of Saraighat was fought here thus giving it a historical importance. The first rail-cum-road bridge across the Brahmaputra was kept to traffic in April 1962 at Saraighat. The old Sanskrit name for the Brahmaputra river is Lauhitya and the local name in Assam is Luit. The native inhabitants, i.e., the Bodos called the river Bhullam-buthur. This term means `making a gurgling sound`. The term was later sanskritised into Brahmaputra.

Course of Brahmaputra River in Bangladesh
In Bangladesh, the Brahmaputra is joined by the Teesta River, one of its largest tributaries. After this, Brahmaputra River in Bangladesh splits into two branches. The much larger division continues due south as the Jamuna and flows into the Lower Ganges, locally called Padma, while the older branch curves southeast as the lower Brahmaputra and flows into the Meghna. Both rivers eventually reconverge near Chandpur in Bangladesh and flow out into the Bay of Bengal. However, the actual Brahmaputra River in Bangladesh crosses through the Jamalpur and Mymensingh district. The waters of the Ganges and Brahmaputra feed these rivers. This river system forms the Ganges Delta, which is the largest river delta in the world.

When compared to the other major rivers of India, the Brahmaputra is less polluted. However there have been problems arising. The petroleum-refining units contribute most of the industrial pollution load into the basin. Other medium and small industries too pollute the river to some extent. The main problem facing the river basin is that of constant flooding. Floods have been happening more often in recent years. Deforestation and other human activities have also increased to great extent.