Lake Manasarovar, or Mapham Yum-tso in Tibetan, lies 20 km southeast of Mt. Kailash and is north to Namnani Peak. It is the highest freshwater lake in the world. With an altitude of 4,560m, the lake covers an area of 412 sq. km and has a maximum depth of 70 meters.
Mapham Yum-tso in Tibetan means the 'eternal and invincible jade lake', named to mark the victory of Buddhism over the local Bon Religion in the 11th century. Xuan Zang (600-664), an eminent monk of the Tang Dynasty (618-907), described Mapham Yum-tso in his book Records of Western Travels as 'a jade pond in west'.
Lake Manasarovar enjoys a reputation equal to the holy mountain. It once appeared in many religious records and legends. Indian legend claims it to be a place where Siva and his wife Goddess Woma, daughter of the Himalayas, bathed. Tibetan legend claims it to be where the God Guangcanlong lived. In Buddhist scriptures, the lake is named the 'mother of the rivers in the world'.
Lake Manasarovar is linked to the smaller Rakshas Tal ( known to Tibetans as Lhanag-tso) by the channel called Ganga-chu. On rare occasions, water flows through this channel from Lake Manasarovar to Rakshas Tal; this is said to angur well for the Tibetan people. The channel had long been dry, but water has indeed been flowing between the two lakes in recent years. The two bodies of water are associated with the conjoined sun and moon, a powerful symbol of Tantric Buddhism.