A Union column under Maj. Gen. Horatio Wright, consisting of the Sixth Corps and elements of the Nineteenth Corps, pursued Maj. Gen. Jubal Early’s army as it withdrew from the environs of Washington, D.C. in the summer of 1864. Early had moved down the Shenandoah Valley, beat a Union force at Monocacy, Maryland and threatened the capital with an attack on Fort Stevens. Wright’s force was joined by elements of Gen. George R. Crook’s command, which had accompanied Gen. David Hunter during his retreat through West Virginia. On July 17th, Union cavalry passed through Snickers Gap and attempted to force passage of the Shenandoah River at Snickers Ford, also known locally as Castleman’s Ferry. On the morning of July 18th, the vanguard of the Union infantry moved through Snickers Gap. Col. Joseph Thoburn of Crook’s command led his division downstream to cross the river at Judge Richard Parker’s Ford. Early’s three nearby infantry divisions moved to defend the fords and block the Yankees from crossing. In the afternoon, Maj. Gen. Robert Rodes’s division attacked and shattered Thoburn’s right flank on the Cool Spring plantation. Thoburn's men made a stand behind a stone wall at the river’s edge and beat off three attacks until darkness enabled them to withdraw. Union pursuit of Early was delayed several days.