Chicago

Chicago skyline

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Chicago, city, seat of Cook county, northeastern Illinois, U.S. With a population hovering near three million, Chicago is the state’s largest and the country’s third most populous city. In addition, the greater Chicagoland area—which encompasses northeastern Illinois and extends into southeastern Wisconsin and northwestern Indiana—is the country’s third largest metropolitan area and the dominant metropolis of the Midwest.

Downtown Chicago

The original site for Chicago was unremarkable: a small settlement at the mouth of the Chicago River near the southern tip of Lake Michigan. Indeed, a common notion for the origin of the city’s name is an Algonquian word for a wild leek (or onion) plant that grew locally. However, Chicago’s location at the southwestern end of the vast Great Lakes system could not have been more ideal as the country expanded westward in the 19th century, and perhaps this is reflected in another interpretation of the Native American term as meaning “strong” or “great.” Regardless of which derivation is correct, it was soon recognized that the Chicago River formed a critical link in the great waterway that arose mid-century between the Atlantic Ocean and the Mississippi River. With the rise of railways soon thereafter, the young city became the country’s railway hub, which helped diversify the city’s rapidly growing industrial base. Chicago continued as America’s crossroads with the explosive growth of air travel after World War II, which eased the city’s transition into a postindustrial economy.

Chicago sprawls along the lakeshore and extends inland to meet its suburbs in a ragged line. At its greatest extent, the city is some 25 miles (40 km) from north to south and 15 miles (25 km) from east to west. Area 228 square miles (591 square km). Pop. (2010) 2,695,598; Chicago-Joliet-Naperville Metro Division, 7,883,147; Chicago-Joliet-Naperville Metro Area, 9,461,105; (2020) 2,746,388; Chicago-Naperville-Evanston Metro Division, 7,267,535; Chicago-Naperville-Elgin Metro Area, 9,618,502.