On July 2, Maj. Gen. Robert Patterson's division crossed the Potomac River near Williamsport and marched on the main road to Martinsburg. Near Hoke's Run, Abercrombie's and Thomas's brigades encountered regiments of T.J. Jackson's brigade, driving them back slowly. Jackson's orders were to delay the Federal advance only, which he did, withdrawing before Patterson's larger force. On July 3, Patterson occupied Martinsburg but made no further aggressive moves until July 15, when he marched to Bunker Hill. Instead of moving on Winchester, however, Patterson turned east to Charles Town and then withdrew to Harpers Ferry. This retrograde movement took pressure off Confederate forces in the Shenandoah Valley and allowed Johnston's army to march to support Brig. Gen. P.G.T. Beauregard at Manassas. Patterson's inactivity contributed to the Union defeat at First Manassas.
Result(s): Union victory
Location: Berkeley County
Campaign: Manassas Campaign (July 1861)
Date(s): July 2, 1861
Principal Commanders: Maj. Gen. Robert Patterson [US]; Brig. Gen. Thomas J. Jackson [CS]
Forces Engaged: Brigades
Estimated Casualties: 114 total (US 23; CS 91)