Chicago History: From Trading Post to Global City (Key Dates)

Chicago grew from a trading post at the mouth of the Chicago River in the 1770s to a city of more than 1 million people by 1890. It was incorporated on March 4, 1837, burned in the Great Chicago Fire of October 8–10, 1871, and rebuilt fast enough to host the 1893 World’s Columbian Exposition. Today it is the third-largest U.S. city, with about 2.73 million residents.

Year	Event
1770s	Jean Baptiste Point du Sable settles at the mouth of the Chicago River
1803	U.S. Army builds Fort Dearborn
1812	Fort Dearborn destroyed after the Battle of Fort Dearborn (rebuilt 1816)
1833	Chicago incorporated as a town (August 12)
1837	Chicago incorporated as a city (March 4); about 4,000 residents
1848	Illinois & Michigan Canal completed
1871	Great Chicago Fire, October 8–10
1885	Home Insurance Building completed, often called the first skyscraper
1890	Population passes 1 million
1893	World’s Columbian Exposition, May 1–October 30
1897	Elevated Union Loop opens (September 6)
1900	Chicago River reversed via the Sanitary and Ship Canal
1909	Citywide address system takes effect (September 1)
1933–34	Century of Progress International Exposition
1942	First self-sustaining nuclear chain reaction at the University of Chicago
1974	Sears (now Willis) Tower completed
1983	Harold Washington becomes Chicago’s first Black mayor
2006	Cloud Gate (“the Bean”) dedicated in Millennium Park
2023	Brandon Johnson inaugurated as the 57th mayor

Founding: du Sable, Fort Dearborn and incorporation

The site was home to Native peoples long before Europeans arrived, and its name was first recorded in 1688 as “Chigagou,” an Algonquian word. Jean Baptiste Point du Sable, a Black man of Haitian origin, arrived in the 1770s and set up a trading post where Michigan Avenue now meets the river. He is recognized as Chicago’s first permanent non-Indigenous settler.

The U.S. government built Fort Dearborn near the river mouth in 1803. It was destroyed after the Battle of Fort Dearborn in 1812, rebuilt in 1816 and torn down for good in 1857. The fourth star on the city flag honors it.

Chicago became a town on August 12, 1833, and a city on March 4, 1837, with about 4,000 residents. William B. Ogden was the first mayor. The Illinois & Michigan Canal, completed in 1848, connected the Great Lakes to the Mississippi River system and set up Chicago as a transportation hub.

Boom years and raising the city

Chicago grew at a remarkable pace. The population reached 109,000 in 1860 and 503,000 in 1880, then more than doubled to over 1 million by 1890. In the 1850s, the city raised its streets five to eight feet to install a sewer system on the low, swampy ground.

The Great Chicago Fire of 1871

The Great Chicago Fire started on the night of October 8, 1871, and rain put out the last flames on October 10. It killed an estimated 300 people, destroyed more than 17,000 structures across more than three square miles, and left about one-third of residents homeless. Choose Chicago puts the number left homeless at more than 100,000.

The fire burned through the central business district, jumped the Main Stem of the river and destroyed nearly all of the North Division. A dry season, strong winds and a city built mostly of wood fed it. The legend of Mrs. O’Leary’s cow persists, but the City Council passed a resolution in 1997 clearing her and the cow.

Rebuilding and the first skyscrapers

Rebuilding drew architects and engineers to Chicago and made the city a laboratory for tall buildings. The Home Insurance Building at Adams and LaSalle streets, completed in 1885, was 12 stories and 180 feet tall. It is widely called the world’s first skyscraper because of its metal frame, and it was demolished in 1931.

Architects including Jenney, Burnham, Root and Holabird developed new building techniques in the Loop, and later decades added modernist and postmodern towers. Explore more in Arts and history.

The world’s fairs: 1893 and 1933–34

World’s Columbian Exposition (1893)

Chicago beat New York for the right to host a fair marking 400 years since Columbus’s arrival in the Americas. The World’s Columbian Exposition ran from May 1 to October 30, 1893, in Jackson Park, about seven miles south of the Loop. Daniel Burnham led construction, Frederick Law Olmsted planned the grounds, and the white neoclassical buildings earned the name “White City.”

More than 20 million people attended despite the Panic of 1893. The mile-long Midway Plaisance featured George Ferris’s giant wheel. The Field Museum opened in 1894 in the fair’s former Palace of Fine Arts.

Century of Progress (1933–34)

The Century of Progress International Exposition marked Chicago’s centennial on the lakefront at Northerly Island and in Burnham Park. It opened May 27, 1933, reopened for a second season on May 26, 1934, and closed October 31, 1934. Its theme was technological progress, shown in Art Deco design.

The Great Migration

Between about 1910 and 1970, hundreds of thousands of Black Southerners moved to Chicago in the Great Migration. Chicago had about 40,000 Black residents in 1910 and about 278,000 by 1940. A first wave lasted roughly through 1940, and a larger second wave began after 1940.

Migrants built Chicago’s Black industrial working class and laid foundations for Black political power, business and union activism. Southern migrants shaped Chicago blues, gospel, food and churches, and the Bronzeville neighborhood became a center of Black arts in the 1930s and 1940s. The city also saw violent resistance: the race riot of July 27 to August 3, 1919, killed 38 people. See the Bronzeville guide.

The 20th century

In 1942, scientists at the University of Chicago produced the first self-sustaining nuclear chain reaction. Chicago remained a manufacturing, rail and meatpacking powerhouse for much of the century.

Richard J. Daley was mayor from 1955 until his death in December 1976. Jane Byrne became the first woman mayor in 1979, and Harold Washington became the first Black mayor in 1983. Richard M. Daley, the elder Daley’s son, served from 1989 to 2011, making him the longest-serving mayor in city history.

The Sears Tower, now Willis Tower, was completed in 1974 at 1,451 feet. It was the world’s tallest building until 1998.

Modern Chicago

Since 2000 the city has added Millennium Park, where Anish Kapoor’s Cloud Gate was dedicated on May 15, 2006, and the Chicago Riverwalk along the Main Stem. In 2021, the outer Lake Shore Drive was renamed Jean Baptiste Point DuSable Lake Shore Drive to honor the city’s first settler.

Rahm Emanuel was mayor from 2011 to 2019 and Lori Lightfoot from 2019 to 2023. Brandon Johnson was inaugurated as the 57th mayor on May 15, 2023. The 2020 Census counted 2,746,388 residents, and the Census Bureau estimated 2,731,585 as of July 1, 2025. See Chicago government.

Frequently asked questions

When was Chicago founded?

Chicago was incorporated as a town on August 12, 1833, and as a city on March 4, 1837. Its first permanent non-Indigenous settler, Jean Baptiste Point du Sable, arrived in the 1770s.

How did the Great Chicago Fire start?

No one knows the exact cause. It began on the West Side on the night of October 8, 1871; the City Council cleared Mrs. O’Leary and her cow in 1997.

How many people died in the Great Chicago Fire?

An estimated 300 people died, and about one-third of the city’s residents lost their homes.

What was the first skyscraper?

The 12-story Home Insurance Building, completed in Chicago in 1885, is widely called the first skyscraper.

How many world’s fairs has Chicago hosted?

Two major ones: the 1893 World’s Columbian Exposition and the 1933–34 Century of Progress International Exposition.