
Census Bureau's metropolitan statistical area (9.6 million people) or the combined statistical area (almost 10 million residents), often called Chicagoland. Chicago is the principal city of the Chicago metropolitan area, defined as either the U.S. Chicago is the county seat of Cook County, the second-most populous county in the U.S., while a small portion of the city's O'Hare Airport also extends into DuPage County. With a population of 2,746,388 in the 2020 census, it is also the most populous city in the Midwestern United States and the fifth-most populous city in North America. state of Illinois, and the third-most populous city in the United States, following New York City and Los Angeles. Chicago ( / ʃ ɪ ˈ k ɑː ɡ oʊ/ ( listen) shih- KAH-goh, locally also / ʃ ɪ ˈ k ɔː ɡ oʊ/ shih- KAW-goh ), officially the City of Chicago, is the most populous city in the U.S.
