What is the border between Gansu and Xinjiang?

The border area between the two places is located in Mazong Mountain.

Mazongshan is a long and narrow belt that separates the two areas. Mazong Mountain is located in Subei Mongolian Autonomous County, Jiuquan City, Gansu Province. It is the frontier area of frontier fortress and plays an important role as a barrier and buffer zone in history. It used to be the front line of confrontation between Huns and the Central Plains during the Han Dynasty, the Three Kingdoms and the Western Jin Dynasty, and it also became the front line of confrontation between Turks and the Central Plains during the Sui and Tang Dynasties.

Mazongshan Town (also known as "in-laws Spring") is the administrative unit of this area, which is located on the generalized black Gobi landform. Mazongshan Town is not only a checkpoint, but also a historical site, and now it has become a tourist attraction.