Chicago is the most populous city in the U.S. state of Illinois and in the Midwestern United States. Located on the western shore of Lake Michigan, it is the third-most populous city in the United States, with a population of 2.74 million at the 2020 census. The Chicago metropolitan area has approximately 9.62 million residents according to the 2020 census and is the third-largest metropolitan area in the country. Chicago is the county seat of Cook County, the second-most populous county in the U.S.
Chicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed. It grew rapidly in the mid-19th century. In 1871, the Great Chicago Fire destroyed several square miles and left more than 100,000 homeless, but Chicago's population continued to grow. Chicago made noted contributions to urban planning and architecture, such as the Chicago School, the development of the City Beautiful movement, and the steel-framed skyscraper.
Chicago is an international hub for finance, culture, commerce, industry, education, technology, telecommunications, and transportation. It has the largest and most diverse finance derivatives market in the world, generating 20% of all volume in commodities and financial futures alone. O'Hare International Airport is routinely ranked among the world's top ten busiest airports by passenger traffic, and the region is also the nation's railroad hub. The Chicago area has one of the highest gross domestic products (GDP) of any urban region in the world, ranking sixth globally, generating over $919 billion in 2024. Chicago's economy is diverse, with no single industry employing more than 14% of the workforce.
Chicago is a major destination for tourism, with nearly 57 million people visiting its cultural institutions, Lake Michigan beaches, restaurants, and other tourist sites in 2025. Chicago's culture has made significant contributions to the visual arts, literature, film, theater, comedy (especially improvisational comedy), food, dance, and music (particularly jazz, blues, soul, hip-hop, gospel, industrial, and electronic dance music, especially house music). Chicago is home to the Chicago Symphony Orchestra and the Lyric Opera of Chicago, while the Art Institute of Chicago has an influential visual arts museum and art school. The Chicago area is home to the University of Chicago, Northwestern University, and the University of Illinois Chicago, among other institutions of higher education. It also hosts the Barack Obama Presidential Center. Professional sports in Chicago include all major professional leagues, including two Major League Baseball teams. The city also hosts the Chicago Marathon, one of the World Marathon Majors.
The name Chicago is derived from a French rendering of the indigenous Miami–Illinois word šikaakwa, which was a name for a wild relative of onion and garlic known to modern botanists as Allium tricoccum. The first known reference to the site of the city of Chicago as "Checagou" was by Robert de La Salle around 1679 in a memoir. Henri Joutel, in his journal of 1688, noted that the eponymous wild "garlic" grew profusely in the area. According to his diary of late September 1687:
... when we arrived at the said place called "Chicagou" which, according to what we were able to learn of it, has taken this name because of the quantity of garlic which grows in the forests in this region.
The city has had several nicknames throughout its history, such as the Windy City, Chi-Town, Second City, and City of the Big Shoulders.
18th century: Potawatomi, Jean Baptiste Point du Sable
In the mid-18th century, the area was inhabited by the Potawatomi, an indigenous tribe who had succeeded the Miami, Sauk and Meskwaki peoples in this region.
The first known permanent settler in Chicago was a trader, Jean Baptiste Point du Sable. Du Sable was of African descent, perhaps born in the French colony of Saint-Domingue (Haiti), and he established the settlement in the 1780s. He is commonly known as the "Founder of Chicago".
In 1795, following the victory of the new United States in the Northwest Indian War, an area that was to be part of Chicago was turned over to the U.S. for a military post by native tribes in accordance with the Treaty of Greenville.
19th century: Growth, major engineering projects
1800–1849: Indian removal, first railroad and canal
In 1803, the U.S. Army constructed Fort Dearborn, which was destroyed during the War of 1812 in the Battle of Fort Dearborn by the Potawatomi before being later rebuilt.
After the War of 1812, the Odawa, Ojibwe, and Potawatomi tribes ceded additional land to the United States in the 1816 Treaty of St. Louis. The Potawatomi were forcibly removed from their land after the 1833 Treaty of Chicago and sent west of the Mississippi River as part of the federal policy of Indian removal.
On August 12, 1833, the Town of Chicago was organized with a population of about 200. Within seven years it grew to more than 6,000 people. On June 15, 1835, the first public land sales began with Edmund Dick Taylor as Receiver of Public Monies. The City of Chicago was incorporated on Saturday, March 4, 1837, and for several decades was the world's fastest-growing city.
As the site of the Chicago Portage, the city became an important transportation hub between the eastern and western United States. Chicago's first railway, Galena and Chicago Union Railroad, and the Illinois and Michigan Canal opened in 1848. The canal allowed steamboats and sailing ships on the Great Lakes to connect to the Mississippi River.
A flourishing economy brought residents from rural communities and immigrants from abroad. Manufacturing and retail and finance sectors became dominant, influencing the American economy. The Chicago Board of Trade (established 1848) listed the first-ever standardized "exchange-traded" forward contracts, which were called futures contracts.