Khorgo mountain is an extinct volcano, which lies east of the Terkhiin Tsagaan lake. The Khorgo volcano is covered with basalt. It has been protected since 1965, fully in 1997, to safeguard spectacular mountain scenery and endangered fauna und flora. The grasslands are rich in wild flowers notably Edelweiss. Torrents of lava issuing from the Khorgo volcano blocked the north and south Terkh rivers, so forming the dammed lake of TerkhiinTsagaan Lake at an altitude of 2060 meters above sea level.