| 21st Iowa Infantry Regiment | |
|---|---|
 Iowa state flag | |
| Active | August 25, 1862, to July 15, 1865 |
| Country | United States |
| Allegiance | Union |
| Branch | Infantry |
| Equipment | .577 Enfield Rifles |
| Engagements | Battle of Hartville (MO) Battle of Port Gibson Battle of Champion Hill Battle of Big Black River Bridge Siege of Vicksburg Siege of Jackson Siege of Fort Blakeley Battle of Spanish Fort |
The 21st Iowa Infantry Regiment was an infantry regiment that served in the Union Army during the American Civil War.