Chicago is a major city in the state of Illinois. The city is the largest in the Midwest and the third-most populous city in the United States, with approximately 2.9 million people. The Chicago Metropolitan area, sometimes informally called Chi-town or Chicagoland, has a population of 9.4 million in Illinois, Wisconsin, and Indiana making it the third largest in the United States.[1] Chicago is located along the southwestern shore of Lake Michigan and is a center of transportation, industry, politics, culture, finance, medicine and higher education. Chicago is informally called the "Second City," the "Windy City," the "City of Big Shoulders" (from Carl Sandburg's poem Chicago), and "Chi-town."

Chicago was founded 1833 as a town to link the Great Lakes with the Mississippi River system. It soon became a transportation hub of the Old Northwest, with major connections by steamboats, canals and (by 1855), railroads. By 1890 it was one of the ten most influential world cities.