Namtso lake or Nam tso lake in Tibet China. Nam Tso Lake is the second largest lake in Tibet, and one of the most famous places on the "Roof of the World". The lake itself is located at an altitude of 4,718 m, and has an area of 1,920 km². This lake is the largest of the lakes in the Tibet Autonomous Region, although it is not the largest on the Qinghai Tibet Plateau, a title that belongs to Lake Qinghai, more than twice the area of Namtso, which is more than 1,000 km, in the northeast, in Qinghai province.