where is chicago

Chicago is the most populous city in the U.S. state of Illinois and the Midwestern United States. It is located on the western shore of Lake Michigan in northeastern Illinois. Chicago is the third-largest city in the United States by population and serves as the seat of Cook County. The city lies mainly on a relatively flat glacial plain with an average elevation between 579 and 600 feet above sea level. Chicago spans about 25 miles north to south and 15 miles east to west, with its downtown area near the lakefront and the Chicago River.