Union General Ulysses S. Grant appoints General Philip Sheridan commander of the Army of the Shenandoah. Within a few months, Sheridan drove a Confederate force from the Shenandoah Valley and destroyed nearly all possible sources of Rebel supplies, helping to seal the fate of the Confederacy.
In the summer of 1864, Confederate General Robert E. Lee had sent part of his army at Petersburg, Virginia, commanded by Jubal Early, to harass Federal units in the area of the Shenandoah and threaten Washington, D.C. The Confederates had used the same strategy in 1862, when General Thomas J. "Stonewall" Jackson effectively relieved Union pressure on Richmond with a campaign in the Shenandoah.
In July, Early marched his army through the valley and down the Potomac to the outskirts of Washington, forcing Grant to take some of his troops away from the Petersburg defenses and protect the nation's capital. Frustrated by the inability of Generals Franz Sigel and David Hunter to effectively deal with Early's force in the Shenandoah, Grant turned to General Philip Sheridan, a skilled general who served with him in the west before Grant became the overall commander of Union forces in early 1864. Surprisingly, Grant had placed Sheridan, an effective infantry leader, in charge of the Army of the Potomac's cavalry division for the campaign against Lee. Now Grant handed Sheridan command of the Army of the Shenandoah, comprised of 40,000 troops that included many demoralized veterans of the summer campaign.
Sheridan wasted little time, beginning an offensive in September that routed Early's army and then destroyed most of the agricultural resources of the region. Although this victory is not as famous as Union General William T. Sherman's march through Georgia, which took place at the same time, it may have been even more complete. The Shenandoah Valley, so important throughout the war, was rendered useless to the Confederacy by the end of the fall.