This one in Lachen is a place not to be missed while at Lachen. A freshwater lake, it is one of the highest water bodies in the world for being situated at an altitude of 5,210 m. It is present in the North Sikkim province and is only 5 km away from the south of China border. The lake is situated towards the north-east of Kanchenjunga range. During the winter months, the lake freezes completely.
Present about 5 km ahead of this lake is the Tso Lhamo Lake. With prior permission from the army, one can trek from the Gurudongmar Lake to Tso Lhamo Lake. The Gurudongmar Lake is named after the patron saint of Sikkim—Guru Padmasambhava—and is considered sacred. It is said that he conducted some religious rituals at the place and hence, a part of the lake never freezes even during the coldest months of the year.