Dear Student,
The Ganga basin is a part of the Ganges-Brahmaputra basin draining 1,086,000 square kilometres in Tibet, Nepal, India and Bangladesh. To the north, the Himalaya or lower parallel ranges beyond form the Ganges-Brahmaputra divide. On the west the Ganges Basin borders the Indus basin and then the Aravalli ridge.
The headquarters of the Ganga called the 'Bhagirathi' is fed by the Gangotri Glacier and joined by Alkananda at Devaprayag in Uttarakhand. Enlarged with the waters from its right and left bank tributaries, the Ganga flows eastward till Farakka in West Bengal. This is the northern most point of Ganga Delta.
Regards,
Priya Agrawal.