Namtso or Lake Nam (officially: Nam Co; Mongolian: Tengri Nor; “Heavenly Lake”; is a mountain lake on the border between Damxung County of Lhasa Prefecture and Baingoin County of Nagqu Prefecture in the Tibet Autonomous Region of China, approximately 112 kilometres (70 mi) NNW of Lhasa.
Namtso is renowned as one of the most beautiful places in the Nyainqêntanglha mountain range. Its cave hermitages have for centuries been the destination of Tibetan pilgrims. A surfaced road across Laken Pass at 5186 m was completed to the lake in 2005, enabling easy access from Lhasa and the development of tourism at the lake.
Settlements in the area include Dobjoi, Donggar and Cha'gyungoinba. The Tashi Dor monastery is located at the southeastern corner of the lake.