The Qilian Mountains (Tibetan: མདོ་ལ་རིང་མོ),[a] together with the Altyn-Tagh sometimes known as the Nan Shan,[b] as it is to the south of the Hexi Corridor, is a northern outlier of the Kunlun Mountains, forming the border between Qinghai and the Gansu provinces of northern China.

[1] The range stretches from the south of Dunhuang some 800 km to the southeast, forming the northeastern escarpment of the Tibetan Plateau and the southwestern border of the Hexi Corridor.

The Qilian mountains are the source of numerous, mostly small, rivers and creeks that flow northeast, enabling irrigated agriculture in the Hexi Corridor (Gansu Corridor) communities, and eventually disappearing in the Alashan Desert.

[8] Qilian (祁连) is said to be a Xiongnu word meaning "sky" (Chinese: 天) according to Yan Shigu, a Tang dynasty commentator on the Hanshu.

[9] Sanping Chen (1998) suggested that 天 tiān, 昊天 hàotiān, 祁連 qílián, and 赫連 Hèlián were all cognates and descended from multisyllabic Proto-Sinitic *gh?klien.