Battle of First Manassas: Union Order of Battle

Army of Northeastern Virginia (United States Army)
Brig. Gen. Irvin McDowell

1st Division (Brig. Gen. Daniel Tyler)
.....1st Brigade (Col. Erasmus Keyes)
..........2d Maine Infantry
..........1st Connecticut Infantry
..........2d Connecticut Infantry
..........3d Connecticut Infantry

.....2d Brigade (Brig. Gen. Robert C. Schenck)
..........2d New York Infantry
..........1st Ohio Infantry
..........2d Ohio Infantry
..........Battery E, 2d U.S. Artillery

.....3d Brigade (Col. William T. Sherman)
..........13th New York Infantry
..........69th New York Infantry
..........79th New York Infantry
..........2d Wisconsin Infantry
..........Battery E, 3d U.S. Artillery

.....4th Brigade (Col. Israel B. Richardson)
..........1st Massachusetts Infantry
..........12th New York Infantry
..........2d Michigan Infantry
..........3d Michigan Infantry
..........Battery G, 1st U.S. Artillery
..........Battery M, 2d U.S. Artillery

2d Division (Col. David Hunter)
.....1st Brigade (Col. Andrew Porter)
..........8th New York Infantry
..........14th New York State Militia (known as the 14th Brooklyn and later redesignated 84th NewYork Volunteer Infantry)
..........27th New York Infantry

..........U.S. Infantry Battalion
..........U.S. Marine Corps Battalion
..........U.S. Cavalry Battalion
..........Battery D, 5th U.S. Artillery

.....2d Brigade (Col. Ambrose E. Burnside)
..........2d New Hampshire Infantry
..........1st Rhode Island Infantry
..........2d Rhode Island Infantry
..........71st New York Infantry (with two 12-pounder boat howitzers)
..........Battery A, 1st Rhode Island Light Artillery

3d Division (Col. Samuel P. Heintzelman)
.....1st Brigade (Col. William B. Franklin)
..........5th Massachusetts Infantry
..........11th Massachusetts Infantry
..........1st Minnesota Infantry
..........Battery I, 1st U.S. Artillery

.....2d Brigade (Col. Orlando B. Willcox)
..........11th New York Infantry
..........38th New York Infantry
..........1st Michigan Infantry
..........4th Michigan Infantry
..........Battery D, 2d U.S. Artillery

.....3d Brigade (Col. Oliver O. Howard)
..........3d Maine Infantry
..........4th Maine Infantry
..........5th Maine Infantry
..........2d Vermont Infantry

4th Division (Brig. Gen. Theodore Runyon)
.....Militia Brigade (three-month enlistment regiments)
..........1st New Jersey Infantry
..........2d New Jersey Infantry
..........3d New Jersey Infantry
..........4th New Jersey Infantry

.....Volunteer Brigade (three-year enlistment regiments)
..........1st New Jersey Infantry

..........2d New Jersey Infantry
..........3d New Jersey Infantry
..........41st New York Infantry

5th Division (Col. Dixon S. Miles)
..... 1st Brigade (Col. Louis Blenker)
..........8th New York Infantry
..........29th New York Infantry
..........39th New York Infantry
..........27th Pennsylvania Infantry
..........Battery A, 2d U.S. Artillery
..........Bookwood’s New York battery (later redesignated 2d New York Independent Battery)

.....2d Brigade (Col. Thomas A. Davies)
..........16th New York Infantry
..........18th New York Infantry
..........31st New York Infantry
..........32d New York Infantry
..........Battery G, 2d U.S. Artillery