Altyn-Tagh (also Altun Mountains, Altun Shan; , Pinyin: A'erjin Shan, Wade-Giles: A-erh-chin Shan) is a mountain range in Northwestern China that separates the Eastern Tarim Basin from the Tibetan Plateau. The western third is in Xinjiang while the eastern part forms the border between Qinghai to the south and Xinjiang and Gansu to the north.