| 21st New York Infantry Regiment | |
|---|---|
| Active | May 8, 1861 to May 18, 1863 |
| Country | United States |
| Allegiance | Union |
| Branch | Infantry |
| Engagements | Battle of Gainesville Battle of Groveton Second Battle of Bull Run Battle of South Mountain Battle of Antietam Battle of Fredericksburg |
| New York U.S. Volunteer Infantry Regiments 1861-1865 | ||||
|
The 21st New York Infantry Regiment ("1st Buffalo Regiment") was an infantry regiment in the Union Army during the American Civil War.