Kosi River is one of the important rivers of India as well as Nepal, and its basin is encircled by ridges. These ridges separate the river from the River Yarlung Tsangpo in the north. The Kosi River, also known as the Saptakoshi or Koshi, has shifted over 120 km west from east, over the last 250 years.
In Rigveda, this river has been mentioned as Kausika, and in Mahabharata, it is referred to as Kausiki. In the latter, it has been mentioned that seven rivers together ultimately form the Saptakoshi River. Kosi River offers tourists an opportunity to enjoy fishing. October to December and February to June are the best for fishing here.
Various resorts arrange for permissions from concerned authorities for fishing in the Kosi River. During monsoons, this river is overfilled with rain water, and lots of boulders are found in the riverbed. Therefore, the river flow is irregular and frequently changes its course. Besides, this river causes heavy floods in Bihar and Bangladesh during monsoons.