Namtso Lake Namtso is a mountain lake on the border between Damxung County of Lhasa Prefecture and Baingoin County of Nagqu Prefecture. The lake lies at an elevation of 4,718 m, and has a surface area of 1,920 square kilometres. This salt lake is the largest lake in the Tibet Autonomous Region. However, it is not the largest lake on the Qinghai-Tibet Plateau. That title belongs to Qinghai Lake (more than twice the size of Namtso) which lies more than 1,000 km [650 miles] to the north-east, in China's Qinghai province.