River Ganga is the longest river of India and its basin area covers almost 26 percent of the country. Out of 2,510 km total length, the river flows for a length of 2,071 km in India. The river has three district courses.
The river has its source in the `Gomukh’ cave of the Gangotri glacier in the Kumaon Himalayas, where it is known as the river `Bhagirathi. From the confluence of river Bhagirathi and river Alaknanda at Devprayag, the river is known as Ganges.
The upper course stretches from the source till Hardwar.
The middle course stretches from Hardwar to Rajmahal Hills in Bihar. The river in this course passes through Uttar Pradesh and Bihar and is joined by numerous tributaries, such as Ram Ganga, Gomti, Ghaghara, Gandak, Kosi from the left hand side and Jamuna, Chambal etc from the right hand side. Jamuna is the most important tributary of the river Ganga.
The lower course is in West Bengal. From the Rajmahal hills, the river flows towards south. Near Dhulian in Murshidabad, it is divided into two branches, such as
- Bhagirathi-Hooghly which passes through West Bengal and the other
- Padma (main branch) which passes through Bangladesh and both drains to the Bay of Bengal. The important tributaries in the lower course and Damador, Ajay, Mayurakshi etc. The river creates as extensive delta at its mouth.