A series of mountain ranges run along the northern edge of the Tibetan Plateau. In the west are the Kunlun Mountains. About halfway across the south side of the Tarim Basin, the Altyn-Tagh Range diverges northeast while the Kunluns continue directly east, forming a relatively narrow "V". Inside the "V" are a number of endorheic basins. The eastern end of the Altyn-Shan is near the Dangjin Pass on the Dunhuang-Golmud road in far western Gansu. East of the Altyn-Tagh the border range rises to the Qilian Mountains. The range separates the Tarim Basin, to the north, and Lake Ayakkum, to the south. The range can be divided into three portions. The southwest portion borders the Kunlun Mountains, is very rugged, with peaks reaching more than and many perennial snow fields. The central portion is lower in elevation, around . The eastern portion is higher in elevation, about and consists of a group of smaller ranges oriented in a south-east to north-west trend.