Chungthang is a small town on the confluence of the two major rivers of North Sikkim Lachen Chu and Lachung Chu (Chu stands for river). The Lachen stream from west and Lachung stream from east meets here to form the Teesta which is the most important river in Sikkim.
The valley is believed to have been blessed by Guru Rimpoche. The great Guru is believed to have taken rest at Chungthung on his way to Tibet. The place where he took rest bears his footmark on a stone. Also locals believe that Guru Rimpoche had some rice meal at the spot and he had spread some of the rice in a nearby land. The land still grows rice, a rarity at this altitude.
It is also believed Guru Nanak visited this place and blessed the site where a shrine in his name is also built. With the recent hydropower development in the area, the landscape of Chungthang is changing rapidly and is becoming a major settlement in North Sikkim.