| 51st Regiment Illinois Volunteer Infantry "Chicago Legion" | |
|---|---|
 Illinois state flag | |
| Active | December 24, 1861 to September 25, 1865 |
| Country | United States |
| Allegiance | Union |
| Branch | Infantry |
| Engagements | Battle of Island Number Ten Battle of Stone's River Battle of Chickamauga Battle of Resaca Battle of Kennesaw Mountain Siege of Atlanta Battle of Jonesboro Battle of Franklin Battle of Nashville |
The 51st Regiment Illinois Volunteer Infantry was an infantry regiment that served in the Union Army during the American Civil War.