The area codes that cover downtown Chicago, Illinois, are 312, 872 and 773. Chicago's suburbs are covered by area codes 224, 847, 331, 630 and 708. Gary, Indiana, which is sometimes considered part of the Chicago metropolitan area, is covered by area code 219.
Both 312 and 872 serve the center of downtown Chicago. The area codes' northernmost landmark is North Avenue Beach, while the southernmost landmark is 31st Street Harbor. Both 312 and 872 stretch from the United Center at its western border to Lake Michigan at its eastern border. Major neighborhoods covered by 312 and 872 include the Near North Side and the Chicago Loop.
Area code 773 covers the rest of downtown Chicago, wrapping around area codes 312 and 872. It stretches from the Forest Glen neighborhood in the north of Chicago to Harborside International Golf Center in southern Chicago. The area code's eastern border lies along Illinois' border with Indiana, while its westernmost point is Chicago Midway International Airport. Other major landmarks in area code 773 include Wrigley Field and the South Side neighborhood.
Area codes 224 and 847 cover Chicago's northern suburbs, including Elgin and Arlington Heights. O'Hare International Airport is located in this area code. Area code 708 covers Chicago's southwestern suburbs, including Oak Lawn and Orland Park. Area codes 331 and 630 cover Chicago's far western suburbs, including Wheaton and Oak Brook.