George McLellan
McDowell was replaced by George B. McClellan.
General George B. McClellan
General Irvin McDowell
1861- General McDowell (replaced) 1861- General McClellan (replaced) 1862- Major-General Henry Halleck (replaced) 1863- General McClellan (replaced) 1865- Lieutenant-General Ulysses S. Grant
General McDowell was the first commanding officer of the Union's Army of the Potomac. Under him the Army lost it's first major battle, the battle of Manassas or Bull Run. He was quickly replaced with General George B. McClellan.
Winfield Scott
5
George B. McClellan
battle of bull run
Irvin McDowell
The left side
I think he is a commander or a general.