Altun Shan National Nature Reserve is a large, arid area in the southeast of Xinjiang Autonomous Region, on the northern edge of the Tibetan plateau and the southern edge of the Tarim Basin in northwest China. It surrounds the Kumkol Basin, an endorheic basin in the western third of the Altyn-Tagh mountains. The reserve is sometimes referred to as the "Arjin Mountains Nature Reserve", or "Aerjinshan". The reserve covers the southern portions of Qiemo County and Ruoqiang County of Bayingolin Mongol Autonomous Prefecture in Xinjiang.