The Kansas City metropolitan area is a bi-state metropolitan area anchored by Kansas City, Missouri. Its 14 counties straddle the border between the U.S. states of Missouri (9 counties) and Kansas (5 counties). With 8,472 square miles (21,940 km2) and a population of more than 2.2 million people, it is the second-largest metropolitan area centered in Missouri (after Greater St. Louis) and is the largest metropolitan area in Kansas, though Wichita is the largest metropolitan area centered in Kansas. Alongside Kansas City, Missouri, these are the suburbs with populations above 100,000: Overland Park, Kansas; Kansas City, Kansas; Olathe, Kansas; Independence, Missouri; and Lee's Summit, Missouri.
Chengxian, which belongs to Longnan City, Gansu Province, is located in the south of Gansu Province and the northeast of Longnan City. Chengxian was called Chengzhou in ancient times, Chengzhou in the Western Wei Dynasty and Jiangzhou as a county in the Ming Dynasty. Cheng County has jurisdiction over 14 towns and 3 townships, 15 neighborhood committees and 245 villagers' committees, with a total area of 1676.54 square kilometers, a total population of 269800 and a resident population of 246800, of which the urban population is 120200, and the urbanization rate is 48.7% (2018). Chengxian County is located in the residual vein of the West Qinling Mountains, the terrain is high in the northwest, low in the southeast, between 750m and 2377 meters above sea level, is a warm temperate semi-humid climate, four distinct seasons, moderate cold and warm, known as "Longyou small Jiangnan", "Longyou granary". Chengxian County is rich in natural resources, including mineral resources, water resources, biological resources and so on.