About Chicago, IL

Chicago ( (listen) shih-KAH-goh, locally also shih-KAW-goh), officially the City of Chicago, is a major city the U.S. state of Illinois. It is the most populous city in the state, and the third-most populous city in the United States, following New York City and Los Angeles. 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. 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 International Airport also extends into DuPage County. Chicago is the principal city of the Chicago metropolitan area, defined as either the U.S. Census Bureau's metropolitan statistical area (9.6 million people) or the combined statistical area (almost 10 million residents), often called Chicagoland. It is one of the 40 largest urban areas in the world. Located on the shores of freshwater Lake Michigan, Chicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed. It grew rapidly in the mid-19th century; by 1860, Chicago was the youngest U.S. city to exceed a population of 100,000. Even after the Great Chicago Fire of 1871 destroyed several square miles and left more than 100,000 homeless, Chicago's population grew to 503,000 by 1880 — and then doubled to more than a million within the decade. The construction boom accelerated population growth throughout the following decades, and by 1900, less than 30 years after the great fire, Chicago was the fifth-largest city in the world.