The Chicago metropolitan area or Chicagoland is the metropolitan area associated with the city of Chicago in the United States and its suburbs. It is the area that is closely linked to the city through social, economic, and cultural ties. There are several definitions of the area, the two most common being the area under the jurisdiction of the Chicago Metropolitan Agency for Planning (a metropolitan planning organization), and the area defined by the federal Office of Management and Budget (OMB) as the Chicago-Naperville-Joliet-Gary, IL-IN-WI Metropolitan Statistical Area (MSA).
The metropolitan area may include areas outside the MSA as part of the broader Combined Statistical Area (CSA). The Indiana portion of the area is known as Northwest Indiana, and the Wisconsin portion is known as Kenosha County. The Chicago metropolitan area is sometimes grouped together with Milwaukee and Racine in Wisconsin, creating a megalopolis, gradually spreading toward nearby urban centers like Rockford, South Bend, Benton Harbor, Janesville, and Madison.