The following is a timeline of the history of the city of Chicago, Illinois, United States.

Before the 19th century

1200: The Council of Three Fires, consisting of the Ojibwe, Odawa and Potawatomi people, occupied what would become Chicago since at least the 13th century. 1673: French-Canadian explorers Jacques Marquette and Louis Jolliet, on their way to Québec, pass through the area that will become Chicago. 1677: Father Claude Allouez arrived to try to convert the natives to Christianity. 1682: French explorer René Robert Cavelier, Sieur de la Salle, passes through Chicago en route to the mouth of the Mississippi River. 1687: The first known written reference to what is now known as Chicago came from Robert LaSalle's memoir, referencing the site as "Checagou", derived from a French rendering of the Miami-Illinois word "shikaakwa", referring to the wild leek, garlic and onion that grew abundantly in the area. 1696: Jesuit missionary Francois Pinet founds the Mission of the Guardian Angel. It is abandoned four years later. 1705: Conflicts develop between French traders and the Meskwaki. 1719: The Comanche Indian Tribe settle in the Great Plains and in the Midwest of the United States. 1754: The Illinois Country becomes part of New France, days later The French and Indian War begins with the war against the British. 1763: The Illinois Country falls to British Troops after the defeat of New France. 1775: The Revolutionary War begins with America declaring independence from Britain. 1778: The Illinois Campaign is born under the command of George Rogers Clark to lead the fight against major British outposts scattered across the country. 1780s: Jean Baptiste Point du Sable establishes Chicago's first permanent settlement near the mouth of the Chicago River. 1795: Six square miles (16 km2) of land at the mouth of the Chicago River are reserved by the Treaty of Greenville for use by the United States. 1796: Kitihawa, du Sable's Potawatomi wife, delivers Eulalia Point du Sable, Chicago's first recorded birth.

19th century

1800s–1840s 1803: The United States Army orders the construction of Fort Dearborn by Major John Whistler. It is built near the mouth of the Chicago River. 1812 June 17, Jean La Lime is killed by John Kinzie, making him the first recorded murder victim in Chicago. August 15, the Battle of Fort Dearborn. 1816: The Treaty of St. Louis is signed in St. Louis, Missouri. Ft. Dearborn is rebuilt. 1818: December 3, Illinois joins the Union and becomes a state.

1821: 1821 Treaty of Chicago 1830 August 4, Chicago is surveyed and platted for the first time by James Thompson. Population: "Less than 100". 1833 1833 Treaty of Chicago Chicago incorporated as a town. The Noble-Seymour-Crippen House in Norwood Park, Chicago was built (annexed to Chicago in 1893). April, Saint Mary of the Assumption Catholic Church was founded, later Old St. Mary's. June 26, First Presbyterian Church (Chicago) founded. 1835 August 31, about 800 Potawatomi men gathered for a war dance in Chicago before being removed to west of the Mississippi River. 1836 The Henry B. Clarke House was built. 1837 Chicago incorporated as a city. Chicago receives its first charter. first mayoral election is held Rush Medical College is founded two days before the city was chartered. It is the first medical school in the state of Illinois which is still operating. The remaining 450 Potawatomi left Chicago. 1840 July 10, Chicago's first legally executed criminal, John Stone was hanged for rape and murder. Population: 4,470. 1841 Union Ridge Cemetery in Norwood Park, Chicago (annexed to Chicago in 1893) was established. 1843: Chicago's first cemetery, Chicago City Cemetery, was established in Lincoln Park. 1844: Lake Park designated. 1847 June 10, The first issue of the Chicago Tribune is published. November 3, Kehilath Anshe Ma'arav, the oldest Jewish congregation in Chicago, was founded. 1848 Chicago Board of Trade opens on April 3 by 82 local businessmen. Illinois and Michigan Canal opens and traffic begins moving faster. Galena and Chicago Union Railroad enters operation becoming the first railroad in Chicago 1849 Wauconda is founded.

1850s–1890s 1850: Population: 29,963. 1851 Chicago's first institution of higher education, Northwestern University, is founded. Jewish Graceland Cemetery, aka Hebrew Benevolent Society Cemetery, the oldest existing Jewish cemetery in Chicago, was founded. The Cook County Poor Farm was founded. 1852: Mercy Hospital becomes the first hospital in Illinois. 1853 October: State Convention of the Colored Citizens held in city. Union Park named. Oak Woods Cemetery was founded. 1854 A cholera epidemic took the lives of 5.5% of the population of Chicago. Cook County Cemetery at Dunning, Chicago's first major Potter's field, was founded near the Cook County Poor Farm in Dunning. 1855 Chicago Theological Seminary founded. April 21, Lager Beer riot. Population: 80,000. 1856: Chicago Historical Society founded. 1857 Iwan Ries & Co. Chicago's oldest family-owned business opens, still in operation today, the oldest family-owned tobacco shop. Mathias A. Klein & Sons (Klein Tools Inc.), still family owned and run today by fifth and sixth generation Klein's. Cook County Hospital opens. Hyde Park House built. 1859 McCormick Theological Seminary relocated. Rosehill Cemetery, Chicago's largest cemetery, was founded. 1860 May 16–18, 1860 Republican National Convention, the first United States presidential nominating convention to be held in Chicago. Illinois resident Abraham Lincoln is nominated for president, and goes on to win the 1860 United States presidential election. September 8, the Lady Elgin Disaster. Population: 112,172. Daprato Statuary Company (Currently Daprato Rigali Studios) founded by the Daprato brothers, Italian immigrants from Barga. Graceland Cemetery was founded. 1863 Saint Boniface Catholic Cemetery and Saint Henry Catholic Cemetery, the oldest existing Catholic cemeteries in Chicago, were founded. 1865 May 1, over 100,000 people attended the procession of the State funeral of Abraham Lincoln and the viewing at the Old Chicago Court House. On June 12, Chicago's Lake Park was re-named Lincoln Park in his honor. 867 Confederate prisoners at Camp Douglas (Chicago) died, bringing the total death toll at the camp to 4,454. The majority of the Confederate prisoners were buried in a mass grave at Oak Woods Cemetery. Corporal punishment was abandoned in schools. Population: 178,492. 1866 School of the Art Institute of Chicago founded. Chicago City Cemetery in Lincoln Park was permanently closed, and most of the bodies were moved to other cemeteries in the city. 1867 Construction began on the Water Tower designed by architect W. W. Boyington. Chicago Academy of Music founded. 1868 Rand McNally is formed as a railway guide company. Lincoln Park Zoo founded.

1869 Chicago Water Tower built. The first Illinois woman suffrage convention was held in Chicago The Chicago Club is established. Washington Square Park being developed. 1870 St. Ignatius College founded, later Loyola University Population: 298,977. 1871 October 8 – 10, the Great Chicago Fire. John Jones became the first African-American to hold elected office in Chicago. 1872 Montgomery Ward in business. Establishment of the first Black fire company in the city.

1873: Chicago Public Library established. 1875: Holy Name Cathedral dedicated. 1877 Bohemian National Cemetery was founded. Railroad strike.

1878 Art Institute of Chicago established. Conservator newspaper begins publication. 1879: Art Institute of Chicago founded. 1880 Polish National Alliance headquartered in city. Population: 503,185. 1881 Unsightly beggar ordinance effected. A smallpox epidemic killed around 2,500 people.

1885: Home Insurance Building building was the first skyscraper that stood in Chicago from 1885 to 1931. Originally ten stories and tall, it was designed by William Le Baron Jenney in 1884 Two floors were added in 1891, bringing its now finished height to . It was the first tall building to be supported both inside and outside by a fireproof structural steel frame, though it also included reinforced concrete. A landmark lost to history and is considered the world's first skyscraper. Mount Olivet Catholic Cemetery was founded.

1886 May 4, the Haymarket riot. Chicago Evening Post published (until 1932). 1887: Newberry Library established. 1888: Dearborn Observatory rebuilt. 1889 Hull House founded. Auditorium Building completed. Auditorium Theatre opened. Mount Olive Cemetery was founded. 1890 The University of Chicago is founded by John D. Rockefeller. Population: 1,099,850. 1891 Chicago Symphony Orchestra founded by Theodore Thomas. Provident Hospital founded. Serial killer H.H. Holmes murdered at least 5 people in Englewood, Chicago between 1891-1894. 1892 June 6, The Chicago and South Side Rapid Transit Railroad (later the Green Line (CTA)), Chicago's first 'L' line, went into operation. Masonic Temple for two years, the tallest building in Chicago. Streetcar tunnels in Chicago (under the Chicago River) in use until 1906. Old Chicago Historical Society Building was built. 1893 May 1 – October 30, The World's Columbian Exposition (World's Fair); World's Parliament of Religions held. October 28, Mayor Carter Harrison III was assassinated by Patrick Eugene Prendergast. Sears, Roebuck and Company in business. First Ferris wheel built by George Washington Gale Ferris Jr. Art Institute of Chicago building opens. Monadnock Building completed. Universal Peace Congress held. Chicago Civic Federation founded. 1894 May 11 – August 2, the Pullman Strike. Ženské Listy women's magazine begins publication. Field Museum of Natural History established. 1895: May 7, the Metropolitan West Side Elevated Railroad (later the Blue Line (CTA)) opened. Marquette Building completed. 1896 1896 Democratic National Convention held; Bryan delivers Cross of Gold speech. Campaign "to improve municipal service and politics" begun in 1896. Abeny beauty shop and Tonnesen Sisters photo studio in business. 1897 March 12, The Chicago Elevator Protective Association of Chicago was formed. Later, on July 15, 1901, to become the International Union of Elevator Constructors Local 2. The Union Loop Elevated is completed. National union of meat packers formed. The Chicago Cultural Center, originally the main library of the Chicago Public Library, opened. 1898: National peace jubilee was held. 1899 Cook County juvenile court established. Municipal Art League established. Carson, Pirie, Scott and Company Building constructed.

20th century

1900s–1940s

1900 May 31, The Northwestern Elevated Railroad, later the Red Line (CTA), Purple Line (CTA) and the Brown Line (CTA), opened. Chicago Sanitary and Ship Canal opens; the Chicago River is completely reversed. Municipal Reference Library active (approximate date). Labor strike of machinists. Saint Luke Cemetery was founded. Population: 1,698,575. 1902 Meatpacking strike. Montrose Cemetery was founded. 1903 December 30, Iroquois Theater Fire City Club of Chicago formed. 1905 The Industrial Workers of the World was founded in June Teamsters' strike. Chicago Defender newspaper begins publication. City Hall rebuilding completed. Chicago Federal Building completed. 1906 Municipal court established. The Chicago White Sox defeated the Chicago Cubs in the only all-Chicago World Series. Sinclair's fictional The Jungle published. Chicago Tunnel Company operated a 2 ft. narrow-gauge railway freight tunnel network (until 1959). 1907: Adolph Kroch opens a bookstore which will evolve into Kroch's and Brentano's The Chicago Cubs win their first World Series 1908