Chicago is founded.

Chicago is incorporated as a city.

Four major fires break out on the shores of Lake Michigan in Chicago, Peshtigo, Wisconsin, Holland, Michigan, and Manistee, Michigan including the Great Chicago Fire, and the much deadlier Peshtigo Fire.

Hyde Park and several other Illinois townships vote to be annexed by Chicago, forming the largest United States city in area and second largest in population.

Chicago is selected to host the Columbian Exposition

The Wrigley Company is founded in Chicago, Illinois.

Opening ceremonies for the World's Columbian Exposition are held in Chicago, though because construction was behind schedule, the exposition did not open until May 1, 1893.

The World's Columbian Exposition opens in Chicago.

The troops sent by Grover Cleveland to Chicago to end the Pullman Strike are recalled.

The first American automobile race takes place over the 54 miles from Chicago's Jackson Park to Evanston, Illinois. Frank Duryea wins in approximately 10 hours.

William Jennings Bryan delivers his Cross of Gold speech advocating bimetalism at the 1896 Democratic National Convention in Chicago.

In Chicago, the American Automobile Association is established.

A fire at the Iroquois Theater in Chicago, Illinois kills 600.

The dirigible ''Wingfoot Air Express'' crashes into the Illinois Trust and Savings Building in Chicago, killing 12 people.

The League of Women Voters is founded in Chicago, Illinois.

During the U.S. Republican National Convention in Chicago, U.S. Republican Party leaders gathered in a room at the Blackstone Hotel to come to a consensus on their candidate for the U.S. presidential election, leading the Associated Press to first coin the political phrase "smoke-filled room".

Saint Valentine's Day massacre: Seven people, six of them gangster rivals of Al Capone's gang, are murdered in Chicago, Illinois.

In Miami, Florida, Giuseppe Zangara attempts to assassinate President-elect Franklin D. Roosevelt, but instead shoots Chicago, Illinois Mayor Anton J. Cermak, who dies of his wounds on March 6, 1933.

The Century of Progress World's Fair opens in Chicago, Illinois.

The first Major League Baseball All-Star Game is played in Chicago's Comiskey Park. The American League defeats the National League 4–2.

Outside Chicago's Biograph Theater, "Public Enemy No. 1" John Dillinger is mortally wounded by FBI agents.

The dust bowl heat wave reaches its peak, sending temperatures to 109°F (44°C) in Chicago and 104°F (40°C) in Milwaukee, Wisconsin.

Franklin D. Roosevelt wins the Democratic Party nomination for the fourth and final time at the 1944 Democratic National Convention in Chicago, Illinois.

The German U-Boat U-505 begins its move from a specially constructed dock to its final site at Chicago's Museum of Science and Industry.

In Chicago, the first televised debate takes place between presidential candidates Richard M. Nixon and John F. Kennedy.

Riots in Chicago, Illinois, during the Democratic National Convention.

The Chicago Eight trial opens in Chicago.

In Chicago, the United States National Guard is called in for crowd control as demonstrations continue in connection with the trial of the "Chicago Eight" that began on September 24.

Black Panther Party members Fred Hampton and Mark Clark are shot and killed in their sleep during a raid by 14 Chicago police officers.

The Sears Tower in Chicago is topped out as the world's tallest building.

American Airlines Flight 191: In Chicago, a McDonnell Douglas DC-10 crashes during takeoff at O'Hare International Airport killing 271 on board and two people on the ground.

The roof of the uncompleted Rosemont Horizon near Chicago, Illinois collapses, killing 5 workers and injuring 16.

Cyanide-laced Tylenol kills six people in the Chicago area. Seven are killed in all.

A brutal snowstorm smashes into the Midwestern United States, causing 14 inches (359 mm) of snow in Milwaukee, Wisconsin, and 19 inches (487 mm) in Chicago, where temperatures plunge to -13 °F (-25 °C); 68 deaths are reported

The Harris Theater opens, commencing a renaissance in the Chicago performing arts community.

Millennium Park, considered Chicago's first and most ambitious early 21st century architectural project, is opened to the public by Mayor Richard M. Daley.

The Trump International Hotel and Tower in Chicago is topped off at convert 1389, at the time becoming the world's highest residence above ground-level.