Encompassing 10,286 square mi (28,120 km2), the metropolitan area includes the city of Chicago, its suburbs and hinterland, that span 13 counties across northeast Illinois and northwest Indiana.

With more than six million full and part-time employees, the Chicago metropolitan area is a key factor of the Illinois economy, as the state has an annual GDP of over $1 trillion.

[7] The Chicago metropolitan area generated an annual gross regional product (GRP) of approximately $700 billion in 2018.

Chicagoland has three separate rail networks; the Chicago Transit Authority (CTA), Metra, and the South Shore Line.

The CTA operates elevated and subway lines that run primarily throughout the city, Downtown Chicago, and into some suburbs.

The interurban South Shore Line runs between Downtown Chicago and the northwest Indiana portion of the metropolitan area.

The Chicago metropolitan statistical area (MSA) was originally designated by the United States Census Bureau in 1950.

The term Chicagoland has no official definition, and the region is often considered to include areas beyond the corresponding MSA, as well as portions of the greater CSA.

[citation needed] Colonel Robert R. McCormick, editor and publisher of the Chicago Tribune, usually gets credit for placing the term in common use.

[14] The first usage was in the Tribune's July 27, 1926, front page headline, "Chicagoland's Shrines: A Tour of Discoveries", for an article by reporter James O'Donnell Bennett.

The Tribune was the dominant newspaper in a vast area stretching to the west of the city, and that hinterland was closely tied to the metropolis by rail lines and commercial links.

[18] Illinois Department of Tourism literature uses Chicagoland for suburbs in Cook, Lake, DuPage, Kane, and Will counties,[19] treating the city separately.

According to the Encyclopedia of Chicago, there is no specifically known origin of the phrase, but it has been commonly used among policy makers, urban planners, and in the media.

[27] According to 2022 estimates from the American Community Survey, the largest ancestries in the Chicago metro area were Mexican (18%), African (17.7%), German (12.8%), Irish (9.9%), Polish (8%), Italian (5.9%), English (5.2%), Indian (2.7%), Puerto Rican (2.3%), Filipino (1.7%), Swedish (1.5%), and Chinese (1.4%).

Another exception to this is the West Side, which has a somewhat lower median income, but the western suburbs contain many affluent and upper-middle class areas.

In an in-depth historical analysis, Keating (2004, 2005) examined the origins of 233 settlements that by 1900 had become suburbs or city neighborhoods of the Chicago metropolitan area.

[citation needed] As the Chicago metropolitan area has grown, more counties have been partly or totally assimilated with the taking of each decennial census.

The Chicago metropolitan area is home to the corporate headquarters of 57 Fortune 1000 companies, including AbbVie Inc., Allstate, Kraft Heinz, McDonald's, Mondelez International, Motorola, United Airlines, Walgreens, and more.

A key piece of infrastructure for several generations was the Union Stock Yards of Chicago, which from 1865 until 1971 penned and slaughtered millions of cattle and hogs into standardized cuts of beef and pork.

[36] The Chicago area, meanwhile, began to produce significant quantities of telecommunications gear, electronics, steel, crude oil derivatives, automobiles, and industrial capital goods.

By the early 2000s, Illinois' economy had moved toward a dependence on high-value-added services, such as financial trading, higher education, logistics, and health care.

[41] In addition to the Chicago Loop, the metro area is home to a few important subregional corridors of commercial activities.

The Western Open and BMW Championship are PGA Tour tournaments that have been held primarily at golf courses near Chicago.

Local television channels broadcasting to the Chicago market include WBBM-TV 2 (CBS), WMAQ-TV 5 (NBC), WLS-TV 7 (ABC), WGN-TV 9 (Ind), WTTW 11 (PBS), MeTV 23, WCIU 26 (CW), WFLD 32 (FOX), WCPX-TV 38 (Ion), WSNS-TV 44 (Telemundo), WPWR-TV 50 (MyNetworkTV), and WJYS-TV 62 (The Way).

Radio stations serving the area include: WBBM (AM), WBEZ, WGN (AM), WMBI, WLS (AM), and WSCR.