The main city is situated on the southern bank of the Brahmaputra. At places the width of the river is 6 to 8 km, while its narrowest portion (1.8 km) is in the location of the famous bridge of Saraighat. There are many permanent and temporary islands and beaches in the river. Umananda a permanent island situated close to the city-center provides a unique picturesque environment. The natural drainage system consists of the Bharalu River (a tributary - the Brahmaputra) and its inter-linkages to the beels and to the Brahmaputra river. Apart from Bharalu, many small rivers Morabharalu, Bahini, and Basista flow within the city interconnected with the feeder drains of the city.
Guwahati straddles the valley of the river Bharalu, a small tributary of the river Brahmaputra. It is surrounded by hills, except where the Bharalu discharges into the Brahmaputra today is important because it is close to the seat of power in Assam, is a commercial centre, and is the node that connects six other northeastern Indian states of Arunachal Pradesh, Nagaland, Manipur, Mizoram, Meghalaya and Tripura.