The early summer of 1862 saw the fate of Federal forces in the east taking a serious turn for the worse. McClellan’s greatly anticipated Peninsular Campaign had ground to a halt under the weight of Seven Day’s Battle losses and the commander’s timid approach. The result of four months of campaigning left the Army of the Potomac against the James River and completely out of position to defend Washington. Fearing the Confederate forces, now completely freed from the threat of McClellan’s offensive, would move on Washington before McClellan could return the Union officials in Washington threw together a new army to defend the capital. General Order No. 103 issued on 26 June 1862 combined forces from the Department of the Shenandoah (Banks), Department of the Rappahannock (McDowell), and the Mountain Department (Sigel) and a small cavalry brigade under BG George Bayard to form the Army of Virginia. The new army established a line of defensive along the Rappahannock River. The whole was placed under the command of the bombastic MG John Pope. The command make-up of this army did not portend great success. Indeed, their existence would be a short one.
General Lee, sensing weakness, embarked on a bold plan to dismember the new army and possibly push the Federals to the peace table with a move into Maryland. Splitting his force, he sent “Stonewall” Jackson on a circuitous march around the Union defenses. His route would take him across the upper Rappahannock into the valley to strike the Union supply center at Manassas Junction. Using the Bull Run Mountains for cover he successfully completed an uncontested march through Thoroughfare Gap, united with Stuart’s cavalry, and appeared before a startled and apparently mystified Pope. The Federal reaction was slow and complicated by Pope’s indecision and lack of tactical acumen. Eventually he managed to place two of his three corps (I and II) in position to challenge Jackson. The final corps (III) under McDowell brought up the rear.
As McDowell moved his men toward unification with Pope another serious issue came to his attention. Where was Longstreet’s corps? The location and intent of the missing Confederate corps needed to be determined. It soon became evident that Longstreet would also pass into the valley but Pope could not manage to put his concentration on Jackson aside long enough to order the gaps sealed by a strong force of infantry. Instead, to cover the passages through the mountains BG Bayard’s cavalry was rushed to the west. By Thursday August 27th a thin line of cavalry outposts was established to cover Thoroughfare Gap and some other smaller passages through the mountains. McDowell, at Gainesville, continued to fear for the safety of the Federal left and understood that knowing where Longstreet would emerge had great value. He also realized delaying Longstreet was important and disregarded an order from Pope to move with his “entire force” to Manassas. He detached troops to assist the cavalry troopers at the Gap. Like everything else about this Federal campaign it would be mismanaged. Complying with Pope’s order with the rest of his corps he detailed only a single division (Ricketts) to confront one half of the Army of Northern Virginia. Thus began the string of events that would lead to the Battle of Chapman’s Mill.
1st New Jersey Cavalry prepares to meet the enemy
On Wednesday, 27 August, BG Bayard’s cavalry was ordered toward the Gap to search for the missing Confederate column. By Thursday the 1st New Jersey Cavalry, commanded by English adventurer Col Percy Wyndham, entered the narrow pass of Thoroughfare Gap and started their search. Jackson’s rapid move through the area had littered the roadway with stragglers, who were gathered up by the dozens. From these men it was learned that Longstreet with the remainder of the Army of Northern Virginia would be closing on the Gap very soon. They immediately began the process of preparing a defense. Wyndham had only 200 or so troopers on hand to pose as an obstacle to Longstreet’s passage and knew a force multiplier was necessary if they were to be even marginally successful. Every available axe was commandeered and put to use as his men sought to obstruct the road through the narrow passage. Additionally, small scouting teams were sent out to the western end of the Gap to search for the expected column. These parties were gradually thinned as more and more prisoners had to be escorted to the rear. Eventually, one such team was reduced to just two men, SGM Craig and Corporal Patterson (Co. L). It was not long before the two men saw the tell tale sign of Longstreet’s approach. Huge dust clouds rising over the hills indicated the approach of the enemy column. Undeterred the two men rode forward until they found themselves within ear shot of the Confederate advance guard. An unsuspecting trio from the enemy force moved away from their resting comrades to hurry on alone. As soon as they were out of sight Craig and Patterson pounced on them. Taken prisoner were an officer and two enlisted men who were whisked away by the intrepid pair. With them went the last Federal presence on the western side of the Gap.
On the trip back to friendly lines with their prizes they found the eastern end of the gap well obstructed;
“Trees had been felled all along from one height to the other and immense rocks rolled down the hillsides among them. Earth was cast lightly upon the branches and ravines converted into traps for the unwary; until no horse could expect to pass with life…”
Wyndham deployed some of his carbine equipped troopers dismounted to take advantage of the available cover. The remainder of the 1st New Jersey and the 1st Pennsylvania along with portions of other units arriving to reinforce his effort stood mounted ready to attack any breakthrough. He also sent a courier to Ricketts informing him of the arrival of Longstreet’s column. While his soldiers peered west Wyndham must have been looking over his shoulder to the east searching for the promised infantry support.
The Fight Opens
The Federal troopers did not have long to wait before the appearance of the enemy at the western end of the gap. Longstreet sent an order to MG D. R. Jones to explore the gap. Jones transferred the order downward to the lead brigade commander, COL G. T. Anderson. From his brigade of Georgians Anderson ordered two companies of the 9th Georgia forward as skirmishers. The advance was followed “at proper distance” by the remainder of the brigade (1st GA Regulars, 7th, 8th and the rest of the 9th GA). The rest of the division followed.
About half a mile from the main body they halted and the skirmishers from the 9th Georgia proceeded into the Gap charged with performing a reconnaissance. Moving slowly into the gap the Georgians ran into the Federal cavalry patrols about 0915. Anderson reported that these vedettes were quickly driven through the gap with his skirmishers claiming 3 of the Union troopers killed. No mention was made of the three men taken by Craig and Patterson. They continued unimpeded through the remainder of the gap until they reached the obstacles at the eastern end. Here the well placed and well protected dismounted troopers made effective use of their carbines. The advance of the enemy skirmishers was halted at the abatis.
The unequal firefight demanded the reinforcement of the Confederate effort. Word was sent back for the support to move up. The 20th and 2nd Georgia were called upon to lead the way. The rest of Anderson’s Brigade and COL Henry Benning’s (substituting for the arrested BG Robert Toombs) would follow. It was clear to Wyndham that his troopers would eventually be swamped by growing Confederate strength. He looked again for his support.
As the Confederates were moving Wyndham’s courier reached the infantry column on the Warrenton Pike near Gainesville. McDowell immediately issued an order for BG James Ricketts division to move to “assist Colonel Wyndham, who at 10:15 a. m. reported the enemy passing through Thoroughfare Gap.”
The race for the Gap was on. Ricketts understood the urgency of the matter and turned his division off the crowded road. The cross country march west proved more arduous than time saving. The lead brigade (COL John Stiles with the 11th PA, 83rd NY, and 12th and 13th MA) did not reach Haymarket, three miles short of the gap, until after 1400. Meanwhile Wyndham’s men maintained their blocking action preventing the deployment of a Confederate battery by sweeping the only available position with their rapid fire weapons. Despite their heroic efforts they needed help badly. It was still about two miles away.The Fight at Chapman’s Mill (Campaign Series)