When the attempt to take Petersburg in conjunction with the mine explosion resulted in such a dismal failure, all the operations contemplated in connection with that project came to a standstill, and there was every prospect that the intensely hot and sultry weather would prevent further activity in the Army of the Potomac till a more propitious season.  Just now, however, the conditions existing in the Shenandoah Valley and along the upper Potomac demanded the special attention of General Grant, for, notwithstanding the successful march that Major-General David Hunter had made toward Lynchburg early in the summer, what he had first gained was subsequently lost by strategical mistakes, that culminated in disaster during the retreat he was obliged to make from the vicinity of Lynchburg to the Kanawha Valley.  This route of march uncovered the lower portion of the Valley of the Shenandoah, and with the exception of a small force of Union troops under General Franz Sigel posted aft Martinsburg for the purpose of covering the Baltimore and Ohio railroad, there was nothing at hand to defend the lower valley.

The different bodies of Confederates which compelled Hunter’s retreat were under command of General Jubal A. Early, who had been sent to Lynchburg with Ewell’s corps after the defeat of the Confederate General W. C. Jones near Staunton on the 5th of June, to take command of the Valley District.  When Early had forced Hunter into the Kanawha region far enough to feel assured that Lynchburg could not again be threatened from that direction, he united to his own corps General John C. Breckenridge’s infantry division and the cavalry of Generals J. H. Vaughn, John McCausland.  B. T. Johnson, and J. D. Imboden, which heretofore had been operating in southwest and western Virginia under General Robert Ransom, Jr., and with the column thus formed, was ready to turn his attention to the lower Shenandoah Valley.  At Early’s suggestion General Lee authorized him to move north at an opportune moment, cross the upper Potomac into Maryland and threaten Washington.  Indeed, General Lee had foreshadowed such a course when Early started toward Lynchburg for the purpose of relieving the pressure in front of Petersburg, but was in some doubt as to the practicability of the movement later, till persuaded to it by the representations of Early after that general had driven Hunter beyond the mountains and found little or nothing opposing except the small force of Sigel, which he thought he could readily overcome by celerity of movement.

By rapid marching Early reached Winchester on the 2d of July, and on the 4th occupied Martinsburg, driving General Sigel out of that place the same day that Hunter’s troops, after their fatiguing retreat through the mountains, reached Charlestown, West Virginia.  Early was thus enabled to cross the Potomac without difficulty, when, moving around Harper’s Ferry, through the gaps of the South Mountain, he found his