BuirNuur is not only a very beautiful lake also the largest on east Mongolia, being 21 kilometers wide, 40 kilometers long and covering 615 square kilometers. 3-5 m high sand dyke was formed from surf on southern bank of the lake and in-between them small lakes were formed some of which connected to the largest body of water. Khalkhriver flows into the lake and Orshuun river flows out of the lake, so thicket of willows and sugar canes were grown alongside the lake. The lake water, which is rich of hydro-carbonate, sodium chloride and calcium, is indeed very fresh and clear.
The lake is home to Mirror Carp, Taimen, Chub, Lenok, Amur Graying, Pike, Khadary, Silver Carp, Amur Catfish, Burbot, Whitefish, and Golden Carp. A fishery is developed, and an estimated 300 tones may be landed annually. The main game fish is Amur Carp. Black Stork, White Spoonbill and Little Whimbrel are common.