Army of Virginia Army of Virginia The Army of Virginia was organized as a major unit of the Union Army and operated briefly and unsuccessfully in 1862 in the American Civil War. It should not be confused with its principal opponent, the Confederate Army of "Northern" Virginia, commanded by Robert E. Lee. The Army of Virginia was constituted on June 26, 1862, by General Orders Number 103, from four existing departments operating around Virginia: Maj. Gen. John C. Frémont's Mountain Department, Maj. Gen. Irvin McDowell's Department of the Rappahannock, Maj. Gen. Nathaniel P. Banks's Department of the Shenandoah, and Brig. Gen. Samuel D.
Army of Northern Virginia Gen. J. E. Johnston as it was joined by the Army of the Shenandoah on July 20, 1861, when command was relinquished to General J. E. Johnston. The following day this army fought its first major engagement in the First Battle of Manassas. With the merging of the Army of the Shenandoah, Gen. Joseph E. Johnston took command from July 20, 1861, until May 31, 1862. Under the command of Johnston, the Army immediately entered into the First Battle of Manassas. On October 22, 1861, the Department of Northern Virginia was officially created, officially ending the Army of the Potomac.