October 1861 • to November >
| Provost Guard | Colonel Andrew Porter | |
| Sturgis (Illinois) Rifles | from Headquarters, Div. Potomac | |
| 2nd United States Infantry Regiment | from Defences of Washington | |
| 3rd United States Infantry, Cos.BDGH&K | from Defences of Washington | |
| 4th United States Infantry Regiment | from Defences of Washington | |
| 6th United States Infantry Regiment | from Defences of Washington | |
| 8th United States Infantry, Cos. F&G | from Defences of Washington | |
| 4th United States Cavalry, Cos. A&E | from Defences of Washington | |
| 5th United States Artillery, Battery K | new | |
| Engineer Brigade | ||
| 15th New York Engineer Regiment | from 15th New York Infantry Regiment | |
| 50th New York Engineer Regiment | from Porter’s Div., 3rd Bde. | |
| Regular Engineer Battalion |