< to June • July 1861 • to August >

Commanded by Brigadier General Samuel P. Heintzelman

The Battle of Bull Run was fought on July 21.

Unattached
4th United States Cavalry, Cos. A&E Captain James B. McIntyre
First Brigade Colonel W. B. Franklin
5th Massachusetts Infantry Regiment Colonel S. C. Lawrence (w 7/21) from Dept. Washington 7/16
to Boston to muster out 7/29
11th Massachusetts Infantry Regiment Colonel G. Clark
1st Minnesota Infantry Regiment Colonel W. A. Gorman from Dept. Washington 7/3
4th Pennsylvania Infantry Regiment Colonel John Hartranft refused to extend service on eve of battle and mustered out 7/20
5th Pennsylvania Infantry Regiment Colonel R. P. McDowell remained at Alexandria during battle and mustered out at Harrisburg 7/25
1st United States Artillery, Battery I Captain J. B. Ricketts (w&c 7/21)
Lieutenant E. Kirby
Second Brigade Col. O. B. Wilcox (w&c 7/21)
Colonel J. H. Hobart Ward
11th New York Infantry Regiment Colonel Noah L. Farnham (mw 7/21)
Lt. Colonel John A. Cregier
38th New York Infantry Regiment Colonel J. H. Ward (^ 7/21)
Lt. Colonel Addison Farnsworth
1st Michigan Infantry Regiment Major A. F. Bidwell
4th Michigan Infantry Regiment Colonel D. A. Woodbury
2nd United States Artillery, Battery D Captain Richard Arnold
Third Brigade Col. O. O. Howard
3rd Maine Infantry Regiment Major H. G. Staples
4th Maine Infantry Regiment Colonel H. G. Berry
5th Maine Infantry Regiment Colonel M. H. Dunnell
2nd Vermont Infantry Regiment Colonel H. Whiting