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.
Dangchang County belongs to Longnan City, Gansu Province, located in the south of Gansu Province, northwest of Longnan City. Dangchang as a place name began in the Dangchang State established by Liang Qin in the Eastern Jin Dynasty, and changed to Dangzhou in the early Sui Dynasty. Since then, the organizational system has undergone many changes, and Dangchang County was officially established in 1954. Dangchang County has jurisdiction over 11 towns, 14 townships and 336 administrative villages, with a total area of 3331 square kilometers, a total population of 310400 and a resident population of 278700 (2017). Dangchang County is located in the crisscross zone between the Minshan Mountain system and the West Qinling Mountains on the edge of the Qinghai-Tibet Plateau, with an elevation of 1138-4154 meters above sea level, with a temperate continental climate, mild and humid climate, significant vertical climate, and great differences between the north and the south. Natural resources mainly include mineral resources, animal and plant resources, hydropower resources and so on. In 2017, Dangchang County completed production.