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.
Yanchang County, which belongs to Yan'an City, Shaanxi Province, is located in the north of Shaanxi Province and east of Yan'an City. It is 73 kilometers from east to west and 55 kilometers from north to south, with a total area of 2368.7 square kilometers. The early human activities in Yanchang County can be traced back to the Neolithic Age. Western Jin Tai began two years (266 years), established the establishment of the county. Several changes, to the second year of Tang Guangde (764), because the Yanhe River from the county from west to east into the Yellow River, the name Yanchang County, still in use. The terrain tilts from northwest to southeast, high in the north and south, low in the middle, showing a valley peak type. Is a warm temperate dry continental monsoon climate, spring, summer, autumn and winter four distinct seasons, cold, warm, dry and wet. By 2018, Yanchang County had jurisdiction over one street and seven towns with a resident population of 128500, achieving a GDP of 54.077.