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.
Duolun County, which belongs to Xilingol League of Inner Mongolia Autonomous region, is located at the southern end of Xilingol League and the eastern end of the northern foot of Yinshan Mountain. Longitude 115 °30, longitude 116 °55, latitude 41 °45, longitude 42 °39'. It is connected with Zhenglan Banner in the west, Keshikten Banner in Chifeng City in the north, and Guyuan County, Fengning County and Weichang County in the south. The total area is 3863 square kilometers. In 2011, it was approved to build a central city by the government of Inner Mongolia Autonomous region and Xilingol League. County people's government in Duolun Nur town. It won the honorary title of famous historical and cultural town in China in 2008 and the honorary title of famous landscape tourism town with national characteristics in 2010. In September 2018, he won the title of "China Natural oxygen Bar". On April 18, 2019, the people's Government of Inner Mongolia Autonomous region decided Duolun County.