< to June • July 1861 • to August >
Commanded by:
Colonel David Hunter (w 7/21)
Colonel Andrew Porter
The Battle of Bull Run (Manassas) was fought on July 21.
| First Brigade | Colonel Andrew Porter | |
| 8th New York State Militia | Colonel G. Lyons | to New York to muster out 7/23 |
| 14th New York State Militia | Colonel A. M. Wood (w 7/21) Lt. Colonel Edward B. Fowler |
|
| 27th New York Infantry Regiment |
Colonel Henry W. Slocum (w 7/21) |
Arrived from New York 7/17 |
| 35th New York Infantry Regiment | Colonel A. M. Wood | from Dist. Washington 7/27 |
| 2nd United States Infantry, Cos. C & K 3rd U.S., Cos. B, D, G, H & K 8th U. S., Co. G |
Major George Sykes | |
| 1st United States Cavalry, Cos. A & E 2nd U. S. Dragoons, Co. K 2nd U. S. Cavalry, Cos. B, E, G & I |
Major I. N. Palmer | |
| United States Marine Battalion | Major J. G. Reynolds | |
| Second Brigade | Colonel Ambrose Burnside | |
| 2nd New Hampshire Infantry Regiment | Colonel Gilman Marston (w 7/21) Lt. Colonel Frank S. Fiske |
|
| 1st Rhode Island Infantry Regiment | Major J. P. Balch | left for Rhode Island to muster out 7/25 |
| 2nd Rhode Island Infantry Regiment | Colonel J. S. Slocum (k 7/21) Lt. Colonel F. Wheaton |
|
| 1st Rhode Island Artillery, Battery A | Captain William H. Reynolds | |
| 71st New York Infantry Regiment | Colonel H. P. Martin | left for New York to muster out 7/31 |