This is an incomplete list of all military confrontations that have occurred within the boundaries of the modern U.S. State of Illinois since European contact.
| Name | Date | Location | War | Result | Dead | Belligerents |
| Battle for Grand Kaskaskia | September 18, 1680 | Near Present-day Ottawa, Illinois | Beaver Wars | Iroquois Victory | ~880[1] |  France and Tamaroa vs Iroquois |
| Siege of Fox Fort | August–September 1730 | Present-day McLean County, Illinois | Fox Wars | French and Allied Victory | ~500[2] | France and Native Allies vs Meskwaki |
| Capture of Fort Gage | July 5, 1778 | Present-day Kaskaskia, Illinois | American Revolutionary War | US Victory | 0 | .svg.png) United States vs .svg.png) Great Britain |
| Battle of St. Louis | May 25, 1780 | Present-day Cahokia, Illinois and St. Louis, Missouri | Anglo-Spanish War | Spanish/US Victory | 25+ | United States and .svg.png) Spain vs Great Britain and Indian Nations |
| Battle of Fort Dearborn | August 15, 1812 | Present-day Chicago, Illinois | War of 1812 | Potawatomi Victory | 67 | .svg.png) United States vs Potawatomi |
| Battle of Africa Point | April 18, 1813 | near Palestine, Illinois | War of 1812 | Kickapoo Victory | 9 | United States vs Kickapoo |
| Battle of Rock Island Rapids | July 19, 1814 | Campbell's Island, Illinois | War of 1812 | Native Victory | 18+ | United States vs Sauk, Meskwaki and Kickapoo |
| Battle of Stillman's Run | May 14, 1832 | Near present-day Stillman Valley, Illinois | Black Hawk War | Native Victory | 15-17 | United States vs Sauk and Meskwaki |
| Buffalo Grove ambush | May 19, 1832 | Near present-day Polo, Illinois | Black Hawk War | Native Victory | 1+ | United States vs Kickapoo |
| St. Vrain Massacre | May 19, 1832 | Near present-day Pearl City, Illinois | Black Hawk War | Native Victory | 4 | United States vs Ho-Chunk or Sauk and Meskwaki |
| Plum River raid | May 21, 1832 | Near present-day Savanna, Illinois | Black Hawk War | | 0 | United States vs Sauk or Meskwaki |
| Battle of Kellogg's Grove | June 16 and 25, 1832 | Near Kent, Illinois | Black Hawk War | United States Victory | 23+ | United States vs Sauk, Meskwaki and Kickapoo |
| Battle of Waddams Grove | June 18, 1832 | Near Waddams Grove, Illinois | Black Hawk War | United States Victory | 5-9 | United States vs Sauk |
| Battle of Apple River Fort | June 24, 1832 | Near Elizabeth, Illinois | Black Hawk War | United States Victory | 1+ | United States vs Sauk and Meskwaki |
| Illinois Mormon War | June 10, 1844 - September 16, 1846 | Nauvoo, Illinois | | Illinois Victory | ~10 |  Illinois and Illinois Militia vs Nauvoo Legion |
| Charleston riot | March 28, 1864 | Charleston, Illinois | Civil War | | 9 | .svg.png) Union Army vs Copperheads |
| Haymarket Affair | May 4, 1886 | Chicago, Illinois | | | 11 | Chicago Police Department vs Federation of Organized Trades and Labor Unions |
| Battle of Virden | October 12, 1898 | Virden, Illinois | Coal Wars | | 11 | United Mine Workers vs Thiel Detective Service Company |
| Herrin Massacre | June 21–22, 1922 | Herrin, Illinois | Coal Wars | | 23 | United Mine Workers vs Southern Illinois Coal Company |
References