Greater St. Louis is the 23rd-largest metropolitan statistical area (MSA) in the United States,[3][4] the largest in Missouri, and the second-largest in Illinois.

Louis, Missouri—sits in the geographic center of the metro area, on the west bank of the Mississippi River.

During the 17th century, the population of indigenous peoples in the area was well over tens of thousands, including 20,000 in the Grand Village of Illinois.

Pierre Laclede Liguest and his 13-year-old grandson, Auguste Chouteau, selected St. Louis as the site for a French fur trading post in 1764 because it was a rarely flooded area at the confluence of the Mississippi and Missouri Rivers.

After the American Civil War, St. Louis continued to grow into a major manufacturing center due to its access to rail and water transportation.

In 1904, St. Louis hosted the world's fair in Forest Park and the Olympics at Washington University's Francis Field.

There was no more room for expansion within city boundaries and earlier immigrant generations started moving to suburbs that could not be annexed.

During the mid-1960s, construction began on the Gateway Arch and Busch Stadium, in part to help revitalize the central business district.

Greater St. Louis contains several separately-chartered, county-level governmental units that exist independently of the hierarchical municipality-county-state structure.

The East-West Gateway Council of Governments is the federally-designated metropolitan planning organization for the region's transportation infrastructure.

Parts of Greater St. Louis also support a public transportation network that includes bus, as well as the MetroLink light rail which began operating in 1993.

[31] As of 2021, Greater St. Louis is home to eight of Missouri's ten Fortune 500 companies: Centene (#24), Emerson Electric (#181), Reinsurance Group of America (#207), Edward Jones (#295), Graybar (#399), Ameren (#469), Olin Corporation (#472), and Post Holdings (#474).

[32] In addition, the area is home to six Fortune 1,000 companies: Stifel (#633), Peabody Energy (#772), Energizer Holdings (#775), Caleres (#935), Belden (#964), Spire (#999).

As well as two of the Top 50 Largest Private Companies in America, as ranked by Forbes: Enterprise Holdings (#9) and World Wide Technology (#20).

[12] Other notable corporations from the area include Wells Fargo Advisors (formerly A.G. Edwards), Energizer Holdings, and Ralcorp.

Significant healthcare and biotechnology institutions with operations in St. Louis include Pfizer, the Donald Danforth Plant Science Center, the Solae Company, Sigma-Aldrich, and Multidata Systems International.

General Motors continues to produce cars in the St. Louis area, although Chrysler closed its production facility in the region, which was located in Fenton, Missouri.

Despite its purchase by Nestlé, Ralston Purina remained headquartered in St. Louis as a wholly owned subsidiary.

[36] Express Scripts, a pharmaceutical benefits management firm, has its corporate headquarters in the suburbs of St. Louis, near the campus of the University of Missouri–St.

[citation needed] Others are SSM Health Care, Mercy Hospital, and the Tenet Healthcare Corporation chain.