Tsomoriri or Lake Moriri (official name: Tsomoriri Wetland Conservation Reserve), in the Changthang (literal meaning, northern plains) area, is a High Altitude Lake (HAL) with an altitude of 4595m (15080ft) in Ladakh, India and is the largest of the High Altitude Lakes in the Trans-himalayan biogeographic region, entirely within India. It is hemmed between Ladakh in the North and Tibet in the east and Zanskar in the west; the Changthang plateau is the geographical setting with snow peaks that provides the source of water for the Lake. Accessibility to the lake is limited to summer season only. Tsokar means salty lake in local language and salt was extracted from this lake in earlier times, till the end of 1959, for consumption by the local people.

As per a classification of the Himalayan Lakes done on the basis of their origin, there are four groups and Tsomoriri falls under the third group of “Remnant Lakes". The classification as reported states:

The Changthang plateau in the eastern Ladakh represents a landscape of low productive Ecosystems which protects unique floral and faunal species.The area is an extension of the western Tibetan plateau that lies above 4500m (15000ft) msl and supports diverse but low populations of several globally threatened mammals.The Lake's basin could also be categorised as an endorheic basin since it is a closed drainage basin that retains water and allows no outflow to other bodies of water such as rivers or oceans.

The lake is surrounded by the elevated valley of Rupshu with hills rising to 6000m (20000ft). “Changpas", the nomadic migratory shepherds (pastoral community) of yak, sheep, goat, and horses of Tibetan origin and who are engaged in trade and work on caravans in Ladakh region, are the main inhabitants of the area. . Changpa herders use the land of this valley as grazing ground and for cultivation.

The Working Report (2006) of the Planning Commission of the Government of India also reports:

The Korzok Monastery, on the western bank of the lake is 400 years old and attracts tourists and Buddhist pilgrims. Tourism during May – September attracts large number of foreign and local tourists even though tented accommodation is the facility available, apart from a small PWD guest house close to the Lake.

An avifaunal survey of the Lake and its adjoining Nuro Sumdo wetland conducted in July 1996 revealed the following facts:

The need for evolving a strategy and an action plan to preserve the extreme fragility of the lake ecosystem has been recognized with the needed emphasis at the National and International level to develop the lake conservation activity with participation of all stakeholders. The actions initiated in this direction are:

Tsomoriri is an administratively declared Wetland Reserve. Legally, shooting wildlife is prohibited. The State Department of Wildlife has set up a check post near Mahe Bridge at the entrance towards the lake. WWF-India Project has established a field office at Korzok in Rupshu near Tsomoriri for ‘Conservation of High Altitude Wetlands in Ladakh Region’ to carry out surveys, interact with tourists, tour guides, act as information centre and conduct education awareness programmes for locals, tourists etc.

Wildlife Institute of India has also set up a field station at Leh to carry out scientific research in the region. Nature clubs have been set up and Information booklet on the lake published. Efforts of WWF – India has also resulted in the local community declaring Tsomoriri as a ‘Sacred Gift for a Living Planet’ during the Annual Conference held in Nepal in November 2000.

Some of the other achievements so far reported on the Lake’s conservation are:

The Indian Army has committed to support and set up a Nature Interpretation Centre at 'Hall of Fame', Leh.