The 4th Pennsylvania Cavalry on July 2, 1863.

Earlier today, there was some discussion on the Gettysburg Discussion Group about the role of the 4th Pennsylvania Cavalry at Gettysburg on July 2, 1863. By way of background: Brig. Gen. John Buford’s First Cavalry Division was ordered to leave Gettysburg and march to Maryland, where it would spend the rest of July 2 and all of July 3 guarding wagon trains and keeping the Army of the Potomac’s lines of supply, communications, and retreat open. By about noon, Buford’s two brigades had left the battlefield, leaving the left flank of the Army of the Potomac’s position in the air.

Responding to calls by Maj. Gen. Daniel Butterfield, the army’s chief of staff, to send additional cavalry to guard that flank, Maj. Gen. Alfred Pleasonton, the commander of the Army of the Potomac’s Cavalry Corps, sent a single regiment, the 4th Pennsylvania Cavalry, to fill the role that had kept two brigades occupied for most of the morning. The question posed was what was the precise mission of the 4th Pennsylvania Cavalry on July 2, and when did it arrive on the Union flank.

As for the assignment, the 4th PA was supposed to provide screening for the left flank of the Army of the Potomac’s position. Butterfield’s note to Pleasonton of 12:50 states: “the patrols and pickets upon the Emmitsburg road must be kept on as long as our troops are in position.” OR 27, pt. 3, 490. A few minutes later, Butterfield wrote, “[Meade] expected, when Buford’s force was sent to Westminster, that a force should be sent to replace it, picketing and patrolling the Emmitsburg road.” Ibid. From these two dispatches, it’s clear that the 4th was supposed to perform the same duties that Col. William Gamble’s brigade of Buford’s division had been performing before it was pulled out.

As for the timing, I wrote this in an article that appeared in issue 37 of Gettysburg Magazine, in an article about the withdrawal of Buford’s division on July 2:

Gregg sent the 4th Pennsylvania Cavalry. Its numbers were insufficient to cover the entire flank, and it is unclear when these men arrived in the area. The Pennsylvania horse soldiers had come to Gettysburg by way of Hanover after an all-night march, and they were exhausted. By the time they arrived, it was too little, too late, as Longstreet was about to unleash his sledgehammer blow on the Army of the Potomac’s left flank. It is unclear where the responsibility for the failure to replace Buford’s departing troopers lies, but it ultimately must fall upon the Cavalry Corps commander, Pleasonton, for failing to recognize the need to protect the army’s position with a cavalry screen. The Union left flank was left unprotected, leaving it open to the attack that would come that afternoon.

This paragraph appears on p. 71 of the magazine.

Lt. Col. William E. Doster of the 4th Pennsylvania Cavalry wrote in his after-action report of the battle: “At noon of the 2d of July, I was ordered to report with my regiment to Major-General Pleasonton, and was stationed in rear of a battery in the center of our line by a captain on General Pleasonton’s staff. Upon reporting to General Pleasonton in person, I was ordered to return to General Gregg, there being sufficient cavalry at that point, which was done.” (OR vol. 27, Pt 1, 1058-9).

He said more in his post-war memoirs:

…Gregg ordered us into a field of clover on Rock Creek, between Hanover and Taneytown roads. At three I was ordered to accompany a staff officer of General Pleasonton’s with my regiment. We hastened through the crowded roads to what I afterwards learned was Little Round Top, in rear of some artillery, McGilvery’s artillery brigade of Sickles’s corps, where I left my regiment and went with my guide to Pleasonton for instructions. This was the headquarters of our army.

The house was a small cottage on the left of the Taney Town Road, sheltered somewhat by the hill above. Outside were many staff officers and orderlies. Within was Butterfield, Meade, and Pleasonton. They occupied a room that contained the ordinary bedroom furniture of an ordinary Pennsylvania farmer. Their gentlemanly manner and brilliant uniforms contrasted strangely with the surroundings.

Pleasonton begged my pardon for having made me ride so far. There was no need of exposing the cavalry in front. I should rejoin Gregg on the right and tell him to take good care of it. My orderly’s horse was struck by a shell here. I rejoined my regiment, who were very glad to get out of the fearful rain of shell which, directed to the caissons in front of them, dismounted a number of them. On my way back noticed Sickles on a stretcher, smoking a cigar. They said his leg had been shot off in the last charge. This is giving the ‘Solace Tobacco’ a new meaning. By the time I reached Gregg he was just going into camp in the clover field above mentioned. The men were just leaving their horses to run at random to graze and sitting down to make coffee, when a long Rebel infantry skirmish line issues from the woods and advances towards us, while artillery on the edge of the woods reach us with shells. We get our artillery limbered up again, throw out a stronger line, drive them back, and then, in sight of one another, take supper, for the first time since we left Edwards Ferry, with some degree of comfort…..

Thus, the answer is that this lone regiment arrived as Longstreet’s assault was getting ready to step off, far too little and far too late to make any difference at all. Then, the Pennsylvanians were pulled back out of line and sent to re-join the rest of Gregg’s division. They played no role at all in the repulse of Longstreet’s assault.

It’s an interesting question as to what Pleasonton really hoped to accomplish, and also why he failed to send a proper force to screen the left flank in a timely fashion. Had he done so, it’s entirely possible that Sickles would not have moved his 3rd Corps out to the Emmitsburg Road plateau, where his command fought valiantly, but was largely sacrificed to Longstreet’s blow. Pleasonton never said, so we will never know. It’s just one of many egregious failures by him during the Campaign, and undoubtedly the most costly in terms of human life.