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.
Mianning County, which belongs to Liangshan Yi Autonomous Prefecture of Sichuan Province, is located in the southwest of Sichuan Province, in the north of Liangshan Yi Autonomous Prefecture, adjacent to Xiaoxiangling in the east, Xichang and Yanyuan in the south, Muli and Jiulong in the west, and Bodhisattva Gang and Shimian County in the north. The total area is 4420 square kilometers. Mianning is located in the Panxi Rift Valley, and the Anning River and Nanya River originate in the territory. The Yalong River winds through the southwest and is known as the rice granary on the banks of the Anning River. It is a "major county of national grain production" and "a big county for pig transfer". More than 30 kinds of minerals have been proved to be of mining value, among which the reserves of rare earths rank second in the country. Mianning is an old revolutionary base. In 24 (1935), after the long March of the Red Army passed through Mianning, the Red Army was established to enter Sichuan.