A mesa is an isolated, flat-topped elevation, ridge or hill, which is bounded from all sides by steep escarpments and stands distinctly above a surrounding plain. Mesas characteristically consist of flat-lying soft sedimentary rocks capped by a more resistant layer or layers of harder rock, e.g. shales overlain by sandstones. The resistant layer acts as a caprock that forms the flat summit of a mesa. The caprock can consist of either sedimentary rocks such as sandstone and limestone; dissected lava flows; or a deeply eroded duricrust. Unlike plateau, whose usage does not imply horizontal layers of bedrock, e.g. Tibetan Plateau, the term mesa applies exclusively to the landforms built of flat-lying strata. Instead, flat-topped plateaus are specifically known as tablelands.
Derong County, which belongs to Ganzi Prefecture, Sichuan Province, is located in 99 °07 east longitude and 29 °10 'north latitude. Located in the southwest of Sichuan Province, it is located in the middle of the Great Shangri-La Tourism Ring at the junction of Sichuan, Yunnan and Tibet. Derong County belongs to the dry valley of the Jinsha River, which is connected with Batang and Xiangcheng County of Ganzi Prefecture in the north, Shangri-La County of Diqing Prefecture of Yunnan Province in the southeast and Deqin County of Diqing Prefecture of Yunnan Province in the southwest. It is 670km away from the state capital Kangding, 1040 km away from Chengdu (Kangding direction), and about 1477 km from Yunnan to Chengdu. In 2017, Derong County has an area of 2916 square kilometers and has jurisdiction over 3 towns and 9 townships, including 127villages, 3 communities and 251natural villages. By the end of 2017, Derong County has a total population of 25859.