After nearly finding himself trapped in the lower Shenandoah Valley next to Winchester by the arrival of Fremont's Union Mountain army coming from what is now West Virginia and elements of McDowell's Union Rappahannock force coming from the area of Fredericksburg, Virginia, Stonewall Jackson now fought those forces on the 8th and 9th of June 1862 near Harrisonburg, Virginia.
The Shenandoah Valley Campaign from the Battle of Front Royal to Jackson's departure for the Peninsula; notice Cross Keys and Port Republic at the bottom left of the map.
These two battles were the Battle of Cross Keys against Fremont on 8 June 1862, and the Battle of Port Republic on 9 June 1862 against a detachment of McDowell's under James Shields.
CS Major General Thomas "Stonewall" Jackson had already managed to drive US Gen Banks and his force out of the Valley with the great victory at Winchester. Jackson also evaded the trap that sought to close off his route back up the Valley at Front Royal -- now Jackson had to blunt those forces that now pursued him. That is precisely what he would do at these two battles.
At the Battle of Cross Keys, 8 June 1862, in Rockingham County, Virginia, the Confederates under Jackson's subordinate, Richard Ewell, though outnumbered 2 to 1, were able to halt John C. Fremont's attacks, conduct an effecient withdrawal, and burn the bridge over the North River. This allowed Jackson's whole force to face Shields the next day at Port Republic, and Fremont could only listen.
Map of the Action at Cross Keys, Va.
Here is the NPS account of the battle: http://www.cr.nps.gov/hps/abpp/battles/va105.htm
The Battle of Port Republic, 9 June 1862, in Rockingham County, VA, would be the last great battle of Jackson's remarkable Shenandoah Valley Campaign. Here, because of the Confederate success at keeping Fremont at bay, Stonewall Jackson was able to pummell an inferior force in the open field -- the vanguard of the division of US Brigadier General James Shields, commanded by US Brig. Gen. Erastus Tyler. Even though strategically outnumbered, Jackson would dominate this field tactically, actually outnumbering his Yankee foes. Both sides would lose about 800 (CS) to possibly a 1,000 (US) men, but the Union force would be routed from the field, and the Confederates pursued for 5 miles.
The Battle of Port Republic. Notice the force of Fremont unable to engage because the the destruction of the bridge.
Here is the NPS account of Port Republic: http://www.cr.nps.gov/hps/abpp/battles/va106.htm
The forces engaged in these two battles were hardly done with the conflict -- Jackson's Valley army would, within a couple of weeks, march for Richmond, Virginia, to join Robert E. Lee and his Army of Northern Virginia in driving McClellan away from the Southern capital.
The three Union armies involved in the Valley campaign would be the core of a new Union Army formed by Abraham Lincoln: the US Army of Virginia. Each Union army that served in the Valley formed a corps of this new force, which was placed under the command of the victorious, but pompous, western US General, John Pope. This would be the US Army of Virginia that would get a licking at the Second Battle of Manassas. Following that defeat, the three corps would be incorporated into the US Army of the Potomac. Thus, the Rappahannock Department of Irvin McDowell eventually became the I Corps of the Army of the Potomac (famous for its role in the first day at Gettysburg and the death of its commander there, John Reynolds). The Mountain Department of John C. Fremont became the XI Corps of the Army of the Potomac (which was routed at Chancellorsville and at Gettysburg). Finally, the Shenandoah Department of Nathaniel Banks became the XII Corps of the Army of the Potomac (of Dunker Church fame at Antietam and Culp's Hill at Gettysburg).