Chicago listen (help·info) is the largest city in the Midwestern U.S. state of Illinois, as well as the third most populous city in the United States. Known as the "Second City," the "Windy City," the "City of Big Shoulders," and "Chi-town" (along with other nicknames and colloquial nicknames that reflect the city's character), Chicago is located along the southwestern shore of Lake Michigan. When combined with its suburbs and nine surrounding counties in Illinois, Wisconsin, and Indiana, the greater metropolitan area known as Chicagoland encompasses a population of nearly 10 million people.

Growing from its 1833 founding as a frontier town of the Old Northwest into one of the world's premier cities, Chicago is ranked as one of 10 "Alpha" (most influential) world cities. Chicago was the site of the world's first skyscraper, and today is the financial, economical, and cultural capital of the Midwest as well as the transportation and arguably architectural center of the U.S. The city's skyscrapers, local cuisine, political traditions, and sports teams are some of its most recognized symbols.

A resident of Chicago is referred to as a Chicagoan. There is some ambiguity regarding the suburbs - some residents call themselves "Chicagoans" and identify with the central city, while others rarely deal with or visit the central city. Typically, residents of Chicago will identify themselves with one of the many neighborhoods of Chicago. About one-third of central-city Chicagoans are Caucasian, another third African American, around a quarter Hispanic and one-twentieth Asian, with small amounts of other groups filling in the remainder. Chicago also has several dozen distinct neighborhoods to match its ethnic diversity; the city is divided into 77 official community areas.