Lachen River is a major tributary of the Teesta River. It is a snow fed river and is located at an elevation of 9022 feet. Lachen River receives its maximum water supply from the melting of snow in the mountains of the East Himalayan range. Owing to this, the river has more water in the summers. Lachen River is known for sheltering vast orchards of apple and featuring scenic beauty.

Origin and Course of Lachen River
Originating in the Himalayas, the Lachen River flows down all along the road to Gurudongmar Lake. Then after meeting with another small stream named Lachung River, it forms the River Teesta. It meets the river at the town of Chungthang off the North Sikkim Highway. The Lachen River mainly flows in a South-eastern route. The river has no major tributaries and only few small brooks unite with it on its course towards Chungthang. The nearby area of the course of Lachen River is of a harsh and craggy topography. It houses dense vegetation and a rich mixture of species of fauna and flora. Since the mountains seldom have plains lands, these terrace cultivations are a great source of food and farming.

Hydroelectric Project and Dams on Lachen River
An important Hydro-electric power plant is constructed on Lachen River near village Bonsoi, in Sikkim. Lachen Hydroelectric Project is located near the Bonsoi village, in North Sikkim. The plant is built with the aim of utilizing the flowing energy of the waters of the river to generate electricity. To meet the demands, a number of dams are constructed across the river. The generating power at installation is 210 MW.

Attractions of Lachen River
Lachen River is known for scenic beauty and orchards of apple. Often tourists visiting Gurudongmar Lake, Green Lake and Chopta Valley passes through Lachen as it provides wonderful views. Moreover, Lachen River acts as the commencing spot for a number of high altitude treks. Since Lachen is close to the higher reaches of the Himalayas trekkers rest here before setting out for the mountains. Many also spend the previous night in Lachen and experience the stunning beauty of the Gurudongmar Lake in the lap of the Himalayas.