United States Armies in the East
July – August 1861
| Major General Nathaniel P. Banks’ Department of the Shenandoah took over from Major General Robert Patterson’s Department of Pennsylvania after Patterson was unsuccessful in preventing Confederate General Joseph Johnson’s troops from reinforcing Beuregard’s men at Manassas.
Much of Patterson’s army had mustered out at the end of their 90 day enlistments, forcing Banks to almost rebuild the force from scratch. Within a month the Department was merged into the Department of the Potomac. Banks retained command of his troops, but now reported to McClellan. By April of 1862 the Administration’s confidence in McClellan was waning, and Banks would again be given independent command. |
 Nathaniel Banks |
Organization of the Department of the Shenandoah in 1861:
July 1861 • August 1861
Timeline of the Army of the Shenandoah in 1861
| July 19 | Department was created, consisting of the Valley of Virginia, the Counties of Washington and Allegheny in Maryland and such parts of Virginia “as may be covered by the army in its operations.” |
| August 17 | Merged into the Department of the Potomac as Banks’ Division. |