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.
Yingjiang County, which belongs to Dehong Dai Jingpo Autonomous Prefecture of Yunnan Province, is known as "Mengla" in Dai language. it is located in the west of Yunnan Province and northwest of Dehong Prefecture, between longitude 97 °31 "98 °16" east and latitude 24 °24 "25 °20'N, bordering Tengchong City in the northeast, Lianghe County in the southeast, Longchuan County in the south, and Myanmar in the west, northwest and southwest, with a total area of 4429 square kilometers, accounting for 38.4% of the state's land area. The county is 153km away from Fumang City, 735km away from the provincial capital Kunming, 197km away from Myitkyina of Myanmar and 131km away from Myanmar. As of 2016, Yingjiang County has jurisdiction over 8 towns and 7 townships. In 2015, there were 81948 permanent households in the county at the end of the year, with a total population of 316990.