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.
Ansai District, which belongs to Yan'an City, Shaanxi Province, is located in the hinterland of the inland Loess Plateau, the edge of Ordos Basin, in the north of Shaanxi Province, due north of Yan'an City, west of Zhidan County, Jingbian County of Yulin City in the north, Zichang County in the east, and Ganquan County and Baota District in the south. Between longitude 108 °5 "44"-109 °26 "18" east and latitude 36 °30 °45 "- 37 °19" 3 "north. The distance between the north and south lines is 92 kilometers, and the east-west distance is 36 kilometers, with a total area of 2950 square kilometers, accounting for 8.04 percent of the total area of Yan'an. Ansai has been known as the "upper county throat" since ancient times. It is located in the cultural fusion zone in which the national culture of the Central Plains represented by Yangshao culture develops northward and the northern national culture represented by Yinshan rock painting culture develops to the south.