< to June • July 1865
Commanded by Major General Lew Wallace
The Department was abolished on August 1, 1865.
| First Separate Brigade | Brigadier General John R. Kenly |
|
| 3rd Pennsylvania Heavy Artillery, Co. H | Captain William D. Rank | mustered out on 7/25 |
| Second Separate Brigade | Brevet Brigadier General William W. Morris |
|
| 11th Indiana Infantry Regiment | mustered out on 7/26 | |
| 7th New York Heavy Artillery Regiment | mustered out on 8/1 | |
| 2nd United States Artillery, Battys. H&K | Sailed to California with the rest of the regiment | |
| Third Separate Brigade | Brigadier General Henry H. Lockwood |
|
| 8th United States Infantry Regiment | ||
| Fort Delaware | ||
| Ahl’s Delaware Heavy Artillery Co. | mustered out 7/24 |