In March 1864, Lt. Gen. Ulysses S. Grant assumed overall command of the Union armies, east and west. In May, he ordered Maj. Gen. Franz Sigel to cooperate with the Army of the Potomac's spring offensive by advancing up the Valley to disrupt Confederate communications at Staunton and Charlottesville.
On May 15, while Grant and Lee were locked in desperate combat at Spotsylvania Courthouse, Sigel made contact with a Confederate force under former vice president of the United States John C. Breckinridge at New Market. Sigel was defeated and retreated rapidly beyond Strasburg, crossing Cedar Creek by dusk on May 16.
Four days after Maj. Gen. Franz Sigel's defeat at New Market on May 15th, Maj. Gen. David Hunter replaced him as commander of the Department of West Virginia. Hunter's instructions outlined a campaign toward Lynchburg and Charlottesville, its primary objective the destruction of the Virginia Central Railroad, the James River Canal, and major industrial facilities and resources in the Shenandoah Valley. Lt. Gen. Grant ordered Hunter to march eastward and join the Army of the Potomac after the mission was completed.
In the meantime, Breckinridge's division had been called east to reinforce the Army of Northern Virginia at Hanover Junction, and Brig. Gen. William E. ``Grumble'' Jones assumed command of the remaining Confederate forces in the Valley.
On May 26th, Hunter's 8,500-man command initiated the movement. Brig. Gen. William E. "Grumble" Jones surprised Hunter on June 5th at Piedmont, but the he counterattacked , turning the Confederate right flank and killing Jones.
Three days later, Brig. Gen. George Crook's command, numbering 10,000 joined Hunter. Personally commited to a campaign of destruction, Hunter entered Staunton, where his men wrecked miles of railroad tracks and the depot, factories, and mills.
On June 5, Hunter crushed the smaller Confederate army at Piedmont, killing Jones and taking nearly 1,000 prisoners. The disorganized Confederates could do nothing to delay Hunter's advance to Staunton, where he was joined by reinforcements marching from West Virginia.
From Staunton, Hunter continued south, sporadically destroying mills, barns, and public buildings, and condoning widespread looting by his troops.
On June 11, Hunter swept aside a small cavalry force and occupied Lexington, where he burned the Virginia Military Institute and the home of former Virginia Governor John Letcher. Hunter's successes forced Lee to return Breckinridge and to send the Second Corps of the Army of Northern Virginia under Lt. Gen. Jubal A. Early to the defense of Lynchburg. Sending Early to the Valley was a desperate decision that restricted Lee's ability to undertake offensive operations against Grant on the Richmond-Petersburg front.
Hunter crossed the Blue Ridge Mountains and reached his major objective, Lynchburg, on the 17th, even as Early's vanguard began to arrive by rail from Charlottesville..
Manning the Confederate lines was Lt. Gen. Jubal A. Early's II Corps, dispatched by Gen. Robert E. Lee to stop Hunter. Hunter's army reached the outskirts of Lynchburg. After a brief, but fierce engagement, though his troops were numerically superior, Hunter panicked before these seasoned Confederates and retreated the next night.
Early pursued for two days and overtook the fleeing Federals at Liberty, inflicting casualties and capturing wagons but then returned to the Valley and started his troops north to the Potomac River. . Hunter abandoned the valley and retreated into West Virginia.
On August 6th, Grant replaced Hunter with Maj. Gen. Philip H. Sheridan.