List of homicides in Illinois

This is a list of homicides in Illinois. This list includes notable homicides committed in the U.S. state of Illinois that have a Wikipedia article on the killing, the killer, or the victim. It is divided into five subject areas as follows:
 * 1) Multiple homicides – homicides having multiple victims. It includes incidents such as the 1886 Haymarket affair, the 1966 murder of six student nurses by Richard Speck, and the 1982 Chicago Tylenol murders
 * 2) Serial killers – persons who murder three or more persons, with the incidents taking place over more than a month and including a significant period of time between them. This includes John Wayne Gacy, the most prolific serial killer in Illinois history.
 * 3) Organized crime – notable homicides involving the Italian-American organized crime syndicate or crime family based in Chicago. These include the 1929 Saint Valentine's Day Massacre and the 1977 murder of Sam Giancana.
 * 4) Lynchings and race riots – homicides associated with lynching and race riots. These include the 1844 Killing of Joseph Smith and the Chicago race riot of 1919.
 * 5) Single homicides – notable homicides involving a single fatality which do not fall within the scope of one of the above categories. These incidents include the 1924 murder of Bobby Franks by Leopold and Loeb.

This article does not include military battles fought in Illinois. Such battles, including battles fought during the Black Hawk War, may be found at List of battles fought in Illinois.

This article also does not include people who have been executed in Illinois. Such persons are listed separately at List of people executed in Illinois.

Listed in chronological order

Serial killers
Listed in chronological order by date of earliest homicide