Ordered to disrupt Confederate plans for an anticipated offensive, General Alfred Pleasonton led the Army of the Potomac's cavalry corps in a two pronged attack across the Rapphannock River in the early morning hours.  General J.E. B. Stuart's cavalry was taken unawares and a massive mounted action ensued with around 20,000 horsemen involved in close combat with sabre and pistol.  After a ten hours of fighting, Pleasonton's troopers broke off and recrossed the river, ending the largest cavalry battle ever fought in North America.  (By John Osborne) 

After the fall of Front Royal, Union forces under Major General N.P. Banks retreated before Confederate General T.J. Jackson but then attempted to delay the converging enemy columns.  The effort to hold 16,000 Confederates with just 6000 Union troops near Winchester in Frederick County, Virginia failed and Banks and his men were forced to retreat through the town and back towards Maryland.  This was a major blow to Union strategy as it renewed threats on Washington and drew manpower away from the Union advance on Richmond.  (By John Osborne)