| 8th Illinois Infantry Regiment | |
|---|---|
 Illinois flag | |
| Active | April 25, 1861, to May 4, 1866 |
| Country |  United States |
| Allegiance | Union |
| Branch | United States Army Union Army |
| Type | Infantry |
| Engagements | Battle of Fort Henry Battle of Fort Donelson Battle of Shiloh Siege of Corinth Battle of Thompson's Station Battle of Port Gibson Battle of Raymond Battle of Champion Hill Siege of Vicksburg |
| Commanders | |
| Notable commanders | Col. Richard J. Oglesby |
The 8th Illinois Infantry Regiment was an infantry regiment that served in the Union Army during the American Civil War.