The Khar Us Lake National Park is located in western Mongolia in Great Lakes Depression. The park was established in June 1997. It covers an area of 850,000 ha in the Great Lakes Basin in Western Mongolia, forming part of the Altay-Sayan region, a WWF ecoregion. This unique landscape hosts many rare and endangered species, such as Altai mountain sheep or argali, Siberian ibex, snow leopard, and black stork.
The park is also one of the most internationally important wetland sites of Mongolia. In 1999 it was registered as a Ramsar site, providing an important breeding ground and migration stopover for about 268 bird species, of which 10 are globally endangered and 21 nationally threatened.
The outflow from Khar Us Lake goes into a short river called Chono Kharaikh, which flows into another freshwater lake, Khar Nuur (Black Lake), home to some migratory pelicans. The southern end of Khar Nuur flows into Durgun Nuur, which is a large alkaline lake good for swimming. The eastern side of Durgun Nuur is an area of bone-dry desert and extensive sand dunes.