| Unit Name: | 139th Indiana Infantry Regiment |
| Dates: | June 5, 1864 – September 29, 1865 |
| Country: |  United States |
| Allegiance: | Union |
| Branch: | Infantry |
| Size: | Regiment |
| Battles: | American Civil War |
| Disbanded: | September 29, 1865 |
The 139th Indiana Infantry Regiment served in the Union Army between June 5, 1864, and September 29, 1865, during the American Civil War.
The regiment was organized at Indianapolis, Indiana, and mustered in on June 5, 1864. It was ordered to Tennessee and Alabama for railroad guard duty, until late September 1865. The regiment was mustered out on September 29, 1865. During its service the regiment lost eleven men to disease.[1]