Mangan, North Sikkim 56 km. About 200km from Lachen.
Gurudongmar Lake or Gurudogmar Lake is one of the highest lakes in the world, located at an altitude of 17,100 ft (5,210 m). It lies in the district of North Sikkim in the state of Sikkim in India, only some 5 kilometres (3.1 mi) south of Chinese border. The lake can be reached by road from Lachen via Thangu.
This fresh-water lake is located northeast of the Kangchenjunga range in a high plateau area connected with the Tibetan Plateau. Gurudongmar lake provides one of the source streams of the Teesta River. The source of Teesta, the Tso Lhamo Lake, lies some 5 km (3.1 mi) to the east. One can seek permission from the army to trek from Gurudongmar Lake to Tso Lhsmo Lake.The lake remains completely frozen in the winter months from November to Mid-May.