Qilian Mountains (Tsilien Mountains), also known as Nan Shan (Chinese: 南山, literally "Southern Mountains", as it is to the south of Hexi Corridor), is a northern outlier of the Kunlun Mountains, forming the border between Qinghai and the Gansu provinces of northern China.
The Qilian mountains are the source of numerous, mostly small, rivers and creeks that flow northeast, enabling irrigated agriculture in the Gansu Corridor (Hexi Corridor) communities, and eventually disappearing in the Alashan Desert. The best known of these streams is the Ejin (Heihe) River.
The Shiji mentions the "Qilian mountains" together with Dunhuang as the homeland of the Yuezhi. A scholar however has suggested that the name here refers to the mountains now known as Tian Shan, 1,500 km to the west, and Dunhuang may be the Dunhong mountain. Qilian is said to be as a Xiongnu word meaning "sky" by Yan Shigu, a Tang Dynasty commentator on the Shiji.
The mountain range gives its name to Qinghai's Qilian County.
- Association for Asian Studies, Far Eastern Association (U.S.) (2003). The Journal of Asian studies, Volume 62, Issue 1. Association for Asian Studies. p. 262. ISBN 0-691-09676-7.