Defense in Depth at Gettysburg

by Eric J. Wittenberg

Eric Wittenberg during a tour of Gettysburg's
South Cavalry Field, October 2000.

Eric J. Wittenberg, author of several books and articles, and a Civil War Cavalry expert, was kind enough to allow publishing of the following synopsis of General John Buford's Cavalry Defense in Depth the first morning at Gettysburg, July 1 1863.


The article is Copyright 2000 by Eric J. Wittenberg.  None of the contents of this webpage may be reproduced without the express written consent of the owner.


The concept that John Buford employed in the initial defense of Gettysburg is called a "defense in depth."  The theory behind a defense in depth is for the defending force to select a position far from the point that it ultimately wants to defend, so that there is a place to fall back to.  A delaying action is fought, with the idea of slowly making a fighting withdrawal.  The defending force makes use of the terrain to delay the enemy's advance.

Buford recognized the good high ground to the south and east of the town square and elected to fight a defense in depth to hold it until the infantry could come up.  Buford had been consulting with John Reynolds in Emmitsburg on the way to Gettysburg on June 30, and knew how close the infantry was.  He would defend the town from the west and north.  Col. William Gamble on the west side, and Colonel Thomas Devin on the north.

Buford set up his videttes on an arc seven miles long.  Gamble's farthest post was four miles from the town square, Devin's six.  The idea of videttes is to serve as an early warning system.  They make contact with the enemy, fire warning shots, delay as long as possible, and then fall back to the next chosen defensive position.  Gamble covered an arc from the Fairfield Road to the Mummasburg Road.  Devin covered the Carlisle, Harrisburg and York Roads.  The next fall back position from the west was Herr's Ridge (which combines with Belmont School House Ridge), and then finally, the main line of battle was atop McPherson Ridge.

The vidette line of Gamble's brigade was manned by about 275 men.  The farthest post was atop Knoxlyn Ridge at the Whisler blacksmith shop.  Vidette posts were typically manned by three or four men, and commanded by a non-com.  This particular one was commanded by Sgt. Levi Shaffer of the 8th Illinois Cavalry.  Lt. Marcellus Jones of the 8th Illinois commanded the regiment's vidette line.  Early on the morning of July 1, Sgt. Shaffer spotted billowing clouds of dust arising along the Chambersburg Pike, indicating the movement of a large body of men.  Shaffer called for Jones.  Jones watched for a moment, borrowed Shaffer's Sharps carbine, rested it on a fence post, and squeezed off the first shot of the Battle of Gettysburg.  Fired at a range of about 700 yards, it hit nothing.  Instead, it sent up the alarm among Heth's advancing infantry.  Soon, more shots rang out along the vidette line.  It was about 6:00 a.m.  Word was sent back to Buford to let him know that the Confederates had begun to advance.  While he sent for Lt. John Calef's artillery, the surprised Confederates stopped and began to deploy into line of battle, a process that took nearly two full hours.  Just by firing a few shots that hit nothing, Buford bought two hours' time.  In the meantime, Buford sent messengers to Reynolds to try to hurry the infantry to Gettysburg.

In the meantime, the videttes fell back to Herr's Ridge.  There, along with about 500 others of Gamble's brigade (total strength, about 750), they made a stand for the better part of an hour.  Remember, too, that effective strength had to be reduced by 25% due to the fact that one in every four men was given the task of holding horses.  So, the actual strength was about 450.  They stood there for about 45 minutes.  Meanwhile, Calef's three sections of artillery deployed along McPherson's Ridge.  Two section (4 guns) deployed on the Chambersburg Pike and the other two about four hundred yards away, near the spot where Reynolds fell.  The idea was to disperse the guns to create the illusion that Buford actually had more than 6 pieces of artillery at his disposal.

The Confederates, after driving Gamble off Herr's Ridge, then got caught in the valley created by Willoughby Run.  They came under heavy fire there, and it took time for them to regroup and begin to advance up the western slope of McPherson's Ridge.  By this time, it was nearly 9:15.  Buford had already bought more than three hours' time by his stand.  However, he grew worried, as there was still no sign of the advance of Reynolds' infantry.  He went up to the cupola of the Seminary to search for the head of Reynolds' column, worried - he realized that it was just a matter of time before he had to pull back or he ran out of ammo.  As McPherson's Ridge was the chosen spot for the defensive stand, Buford deployed all of Gamble's brigade there, as well as a regiment of Devin's positioned to the north of the railroad cut.  There, they stood for about an hour before the Confederates began pressing them back, both by flanking the position and because Gamble's men were running out of ammunition.

As things looked most desperate, Buford's signal officer, Lt. Aaron B. Jerome, spotted the advance of Reynolds' column, and reported it to Buford.  Buford ascended the cupola again, saw it himself, and said, "Good, now we can hold the place."  He sent a messenger to Reynolds, who spurred ahead to meet with Buford.  Reynolds called out, "What goes, John?"  Buford characteristically replied, "The Devil's to pay!" and pointed out the advancing Confederate infantry.  Reynolds then asked whether Buford could hold, to which the cavalryman responded, "I reckon so."  Buford then came down, and he and Reynolds conferred and rode out to the front to see the situation.

Reynolds then sent his staff officer, Capt. Stephen Minot Weld, to Meade with a situation report, wherein Reynolds said, "Tell the General that we will hold the heights to the south of the town, and that I will barricade the streets of the town if necessary."  Weld rode off to report.  In the meantime, Reynolds gave orders for his infantry, led by Doubleday's division, to come up at the double-quick, which they did, advancing across the fields on the oblique.  As Gamble's men were running out of ammunition, the infantry came up, and Gamble's tired troopers opened ranks to make room for them to come into line.  After being relieved, Gamble's troopers took up a position on the Union left.  The men of the 3rd Indiana Cavalry refused to leave the line of battle, holding a position next to the Iron Brigade.  Meanwhile, Joe Davis was pressing Devin back.  Since Devin had only a regiment and a half atop the ridge, their position was more desperate.  Reynolds responded by calling up John Robinson's division, which arrived just in the nick of time, just before Devin's troopers ran out of ammunition.

This was a perfectly planned and perfectly executed defense in depth, executed with perfect dragoon tactics.  If one reads the manual for this sort of thing, what Buford did was by the letter of the book.

Eric J. Wittenberg
Columbus, OH
2000 by Eric J. Wittenberg

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