Ramganga River: Ramganga River is the lifeline for Corbett National Park. We cannot imagine the existence of Corbett without Ramganga. It is the largest of all the precious water bodies in the park. We can imagine the importance of this river with evidence that it was named Ramganga National Park for a brief period from 1954-1957 before it was named Corbett National Park. The river is fed by rain and originates from the Gairsain region in Lesser Himalayas. The river flows around a stretch of near about 100 kilometers before you get inside the park near Marchula. Approximately, it flows 40 km east to west inside the park till Kalagarh where it meets the plains. It collects water from the Palain, Mandal, and Sonanadi rivers during this run through the park and finally drains into River Ganga near Farrukhabad in Uttar Pradesh.
Kosi: The Kosi is a perennial river that serves a major portion of the Corbett's wild as the Corbett wild use the Kosi river to quench their thirst. The Eastern periphery of the park is fed by Kosi that flows from Mohan to Ramnagar via Dhikuli. Though, the Kosi does not enter the park boundary.
Sonanadi: This Gorgeous river is a significant tributary of the Ramganga River. The river has been named after the Sonanadi wildlife Sanctuary which adjoins Corbett National Park and is held as a crucial part of Corbett Tiger Reserve. It enters Corbett from the North-West direction and merges into the Ramganga River at its reservoir.