Spanning southern Mongolia and northwestern China, the Gobi Desert is a vast expanse, over 1,600km long and up to 1,000km wide, covering 1.3 million sq km. It includes five eco-regions: Gaxun, Junggar, Trans-Altai, Eastern Gobi, and Alxa Plateau, bordered by the Altai, Hangayan, Yin, Qilian, and Tien Shan mountains.