Bor Khyaryn Sand Dunes, 200 km long, are the sand massifs, situated along the longitude in Khunguin River Basin. The sand dunes are stretched to the west to southern Khyargas Lake joining Zavkhan tsagaan Tungyn and Shiir Ovoo Zamyn Khudgyn sand dunes and extend to the east until the east shore of Telmen Lake. The sand dunes span over 5.3 thousand sq.km area, which constitutes 29.3 % of sand dunes of Great Lakes Depression and becomes the second largest sand dunes in Mongolia.
Bor Khyaryn Sand Dunes and its east neighbor Mongol Sand Dunes are 3.4 thousand sq.km long. This sand dunes Is one of the most beautiful branch of sand dunes and richest In water, grass, trees and shrubs as well.
The west part (near Urgamal soum) of Bor Khyaryn Sand Dunes is the pleasant place for pastureland, has rich vegetation cover, and is dominant in grassy and mossy plants. In the central part to the east there are chain of dunes with bigger and sharper angles. These dunes are 1050 m In height and seen as brown due to the coarse grained sand cover.
In the central part (near Bayannuur) of the dunes, there are hump sands with plants and bare sands in the 2 sides of them. In the eastern Bayannuur, we can see sharp angled larger dunes with height of 10-170 m like mountain ranges.
The eastern part of Bor Khyaryn Sand Dunes divides into the parts in the north and southern part of Ulaagchny Khar Lake and called its northern part as Elst and southern part as Mongol Sand Dune. There is a plenty of chain of sand massifs and humps sands to the east from the East Mongol Mountain (2123m). Mountains such as East Mongol, Elsny Shiir, Khuugaa, Tovkhosh, Baga Nuur's Berkn and Shiir Ukhaa are located in the sand massif. The sides and slopes of the mountains have much covered by sand.
Bor Khyaryn Sand Dunes are rich in water supply, Bayan, Ulaagchny Khar, Kholboo and Baga lakes and Olon, Turuun, Mukhart and Khungui Rivers are sourced from the sand dunes. Bayan Lake was originated in the place where Olon and Turuun Rivers flowed into the Khungui River. Khungui River is sourced from the sand dune with a height of 80-90 m. Mukhar Khungui River is flows from 120-130 m high sand dunes. The upper part of Mukhar Khungui River has much seabuckthorn and wicker trees. Local people call these rivers as Burgastai River, Mukhartyn Ekh (Sourse of Mukhart River), Shavart (Muggy), and Nariin (Narrow) River according to their locations and shapes. Also, these rivers have become the source of water supply not only for the locals but also the herds in Erdenekhairkhan, Zavkhanmandal and Urgamal soums. Bor Khyar Sand Dunes look like reddish when they are wet. There also has been rich vegetation cover; many species of rare medicinal plants such as white and black beech grass, bushy and wicker trees , seabuckthorn and dropwort.
These sand dunes have been the home of many species of animals, namely argal sheep, marmot, gazelle, fox, wolf, fox, manul cat, rabbit, black tailed , gazelle ,tree creeper, lizards such as steppe runner, gecko and birds such as pallas's sandgrouse. Bor Khyar Sand Dunes look like yellow brown from far away so it is called Bor
Khyaryn Els (Brown Sand Dunes of Mountain ridge). Researcher Baasan.T notified the Bor Khyar is a sand dune with vegetate cover. Mongolian State Great Khural has protected the sources of Khungui and Mukhar Khungui Rivers under National Park status belonging to Ulaagchnyy Khar Lake National Park according to the degree number 6 since 2006.