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.
Tongguan County, which belongs to Weinan City, Shaanxi Province, is located at the eastern end of Guanzhong Plain in Shaanxi Province. It is bordered by Lingbao City, Henan Province in the east, Huayin City in the west, Luonan County in the south, Dali County in the northwest, and Ruicheng County in Shanxi Province across the Yellow River in the north. It is between longitude 110o 090032 "- 110o 25027" east and latitude 34o 230033 "- 34o 390001" north, with a total area of 526 square kilometers. In 2018, Tongguan County had a resident population of 154200, with a regional gross domestic product (GDP) of 4.035 billion yuan, of which the added value of the primary industry was 484 million yuan, the secondary industry was 1.446 billion yuan, the tertiary industry was 2.104 billion yuan, and the primary, secondary and tertiary industries accounted for 12.0% and 35.8% of the GDP, respectively.