The Battle of Antietam: The Creation of Artillery Hell

by: Major Albert A. Mrozek, Jr.

Though the Union and Confederate artilleries each had advantages and disadvantages in the Battle of Antietam in September of 1862, the artillery with the most initiative and superior fire support coordination prevailed. That artillery persevered, though outnumbered, and withstood counterbattery Hell, though the enemy’s execution of the missions was classic. The prevailing artillery's leaders had more quickly learned organization and command and control lessons from previous campaigns, making their guns more agile to lessen the effects of the enemy’s massed fires and more responsive with close support.

At the outset of the Civil War, both the Union and Confederate armies grappled with the problem of employing large artillery forces effectively and efficiently.  During the first year of the war, both armies attempted to solve the problem by implementing artillery organizational and command and control modifications.

By 1862, the Army of Northern Virginia had organized its artillery into battalions under the command of field grade chiefs of artillery.  The improved fire support coordination afforded by this innovation offset the inferiority of Confederate artillery at the Battle of Antietam and may well have saved the Confederate Army from defeat in that battle.

Before 1861, artillery in the United States consisted of individual batteries scattered throughout the country.  As a result, artillery expertise had diminished to little more than the technical aspects of managing a battery.  Tactics had reverted to the pre-Napoleonic stage of assigning batteries to brigades and even sections to regiments (Jennings C. Wise, The Long Arm of Lee, J.P. Bell Company, Lynchburg, Virginia, 1915).  In effect, artillery had become crew-served weapons for the infantry instead of a true combat arm.

As both sides organized large armies with sizeable artillery forces, officers turned to the Napoleonic model of organization and tactics.  Napoleon created groups of artillery for his divisions and a mass of reserve artillery for the entire army.  The army commander could commit the reserve artillery at the critical time and place in the battle to blast a hole in the enemy infantry ranks.  The French infantry then exploited the breach (Wise).  Under this system, French artillery was a potent offensive weapon.

Improvements in armaments, however, precluded the direct adoption of the Napoleonic model.  The increased range of rifled small arms meant artillery could no longer close within canister range of the infantry ranks.  The maximum effective range of canister was 300 meters, but the rifled Civil War musket could hit a target at 500 meters (L. Van Loan Naisawald, Grape and Canister, Oxford University Press, New York, 1960).

At the same time, rifling increased artillery ranges for shell projectiles.  Rifled guns had a wider zone of fire, so dispersed pieces could now mass fire.  This development made it inefficient to hold a group of guns out of action until the critical time in the battle (Wise).

Combat experience eventually produced a doctrine for artillery.  When on the offense, artillery concentrated on the enemy’s artillery.  In the defense, the enemy’s infantry became the primary target.  In either case, massed fire coordinated with the maneuver of infantry was the key to success (Naisawald).

Confederate Developments

In the summer of 1861, Colonel E. P. Alexander organized five batteries of artillery into a battalion, an artillery formation previously unknown (Wise).  Despite Alexander’s persistent advocation of the tactical utility of artillery battalions, old habits died hard.  When Brigadier General William N. Pendleton was appointed Chief of Artillery of the Confederate Army in Virginia, he promptly assigned batteries to brigades (Wise).

At the First Battle of Bull Run (July 1861), Pendleton’s successful control of the massed fires of three batteries showed both the practicality of Colonel Alexander’s ideas and the value of an artillery reserve (Wise).  As a result, the Confederate Army was reorganized to field two battalions of reserve artillery in February 1862.

The ineffectiveness of the Confederate artillery organization and command and control became apparent on the Virginia Peninsula during the Peninsula Campaign (17 March to 2 September 1862).  The infantry commanders who controlled the direct support artillery overlooked coordination and thought in terms of pressing the battle with their troops.  Also, the artillery frequently moved at the rear of the march column (Wise).  When enemy contact was made, the artillery had no time to provide preparation or counterbattery fires before its fields of fire were masked by the advancing infantry (Wise).

In his memoirs, Colonel Alexander wrote, “Perhaps our greatest deficiency at this period was in the artillery service.  None of our batteries were combined into battalions, but each infantry brigade had a battery attached to it.  There were no field officers of artillery charged with combining batteries and massing them to concentrate heavy fire upon important points” (Wise).

General Pendleton also noted the deficiencies.  When Robert E. Lee assumed command of the Confederate Army in June 1862 and reorganized it, many of Pendleton’s recommendations were implemented.  In addition to the general army reserve, division reserves were created.  Additionally, division chiefs of artillery were given control of all the artillery in their divisions, although brigade commanders still controlled batteries when they were assigned to brigades (Wise).

Between Second Bull Run and the Maryland Campaign, a second major artillery reorganization took place.  An artillery battalion was attached to each division.  A reserve was planned for each corps, and a general reserve was maintained for the army.

To improve command and control each battalion, whether divisional, corps or general reserve artillery, was placed under the command of a field grade officer.  In the divisions, the field grade officer commanding the battalion was also the division chief of artillery, the principle artillery advisor to the commander (Wise).  The combined artillery expertise and command authority of the chief of artillery made him an effective fire support coordinator for the division.

These changes were not fully implemented for the Battle of Antietam.  D.R. Jones’ division had only one battery of artillery, and the two brigades in Walker’s division still had their own batteries (Jay Luvaas and Harold W. Nelson, The US Army War College Guide to the Battle of Antietam, Harper and Row, New York, 1987).  Also, the order of battle shows no reserve battalion for Jackson’s corps.  However, Jeb Stuart’s horse artillery, under Chief of Artillery John Pelham, capably filled the role of Jackson’s reserve artillery (Luvaas and Nelson).

Union Developments

When General George B. McClellan assumed command of the Army of the Potomac in July 1861, his artillery batteries were assigned to brigades and regiments (Naisawald).  As part of McClellan’s reorganization of the army, Major William F. Barry, the Union Chief of Artillery, undertook the task of revamping the artillery.  Each division was assigned four batteries.  Additionally, an artillery reserve for the army numbering 100 guns was formed.  If divisions were organized into corps, at least half of the divisional artillery would constitute the corps reserve (Naisawald).

McClellan’s changes created a sound artillery organization throughout the army, but the command and control of artillery remained inadequate.  Because most Union field grade artillery officers were inexperienced with artillery tactics above the battery level, McClellan decided to grant his chiefs of artillery administrative authority only.  Furthermore, no staffs were authorized to assist the chiefs of artillery (Naisawald).

The problem was further magnified because the division chiefs of artillery were also battery commanders.  In battle, these officers were required to command their own batteries and locate positions for the other batteries in the division (Naisawald).  These two huge responsibilities were more than most officers could accomplish effectively.

Compounding the problem were division commanders who rarely relinquished control of their batteries to their chiefs of artillery.  The old system of infantry commanders controlling the artillery remained alive and well in the Union Army.

Even after Union field grade artillery officers gained experience during the Peninsula Campaign, McClellan did not authorize higher artillery staffs and commands.  These positions were not considered necessary because they were perceived to be unneeded in the past (Naisawald).  As the Army of the Potomac marched toward western Maryland to meet the invading Confederate Army, it absorbed the former army of John Pope.  This act created a new artillery problem.  The two corps (I and XII) added to McClellan’s army had all of their batteries organized into a corps artillery (Luvaas and Nelson).  Brigadier General Henry J. Hunt, McClellan’s new chief of artillery, reassigned the batteries of I Corps to the divisions, but the organization of XII Corps was left intact (Naisawald).

Artillery at Antietam, 16-17 September

The Confederate position (see map) was organized with Jackson’s corps defending north of Sharpsburg from the West Woods to the Sunken Road.  Longstreet’s corps defended south of Sharpsburg from the Boonsboro Turnpike on a line that generally paralleled the Harper’s Ferry Road (Steven W. Sears, Landscape Turned Red, Ticknor and Fields, New Haven, 1983).

The reinforced horse artillery of Jeb Stuart occupied Nicodemus Hill (Position B on the map).  From here they could fire into the flank of the attacking I Corps.  More importantly, the guns could cover the area between the hill and the Potomac River and secure the Confederate northern flank.  A mass of I Corps artillery (augmented later by artillery of the XII Corps) on the high ground north of the Poffenberger farm (map Position A) accomplished the same function for the Union army (Luvaas and Nelson).

The Union offensive consisted of successive but uncoordinated attacks against Jackson’s position by I Corps at 0600, XII Corps at 0730 and II Corps at 0900.  The IX Corps crossed Antietam Creek by 1300 and pressed an attack against Longstreet’s corps, beginning at approximately 1500.

The Union Army had a superior artillery force at the battle in both numbers and quality.  The Army of the Potomac had 293 guns present at Antietam.  The Confederate Army had an estimated 246 guns (Joseph Mills Hanson, “A Report on the Employment of the Artillery at the Battle of Antietam, Maryland,” National Park Service, Petersburg, Virginia, 1940).

In terms of rifled long-range guns (with effective ranges greater than 2,000 yards), the Union army appears to have outnumbered the Confederate army by more than two to one.  The Union artillery had a total of 166 Parrotts and three-inch rifles: 56 percent of the force.  Of the 194 guns of known calibers in the Confederate army, 82 (42 percent) were long-range pieces.

The preferred gun for the division artillery was the 12-pounder Model 1857 Napoleon.  The Napoleon was light, maneuverable and capable of firing all major types of munitions of the era.  Employing canister, the Napoleon was the most effective artillery weapon against infantry (Naisawald).  The Union army fielded 108 Napoleons: 37 percent of its force.  The Confederates had only 27.  Conversely, approximately 23 percent of the Confederate artillery consisted of the obsolete six-pounder smoothbore (Dean S. Thomas, Cannons, An Introduction to Civil War Artillery, Thomas Publications, Gettysburg, Pennsylvania, 1985).

General Hunt took advantage of both the Union superiority in long-range guns and the terrain to provide punishing counterbattery fire.  Hunt positioned the reserve artillery, along with batteries of Parrotts and three-inch rifles from V and VI Corps on the bluffs east of Antietam Creek (map Positions H and K).  These 68 long-range guns had fields of fire that enfiladed parts of the Confederate lines.  More importantly, they covered most of the hills and ridges that were likely Confederate artillery positions.

The severe counterbattery fire inflicted by these guns caused at least one Confederate battalion commander to remember it as Hell.  Stephen D. Lee in a letter to Colonel Alexander said, “Pray that you may never see another Sharpsburg.  Sharpsburg was artillery Hell” (Sears).

As intense as the Union counterbattery fire was, it was not completely effective in silencing the opposing artillery.  Confederate commanders dispersed their batteries to lessen the effects of the massed fire and concealed them in defilades when taken under fire.  When the counterbattery fire shifted, the batteries sprang back into action (Wise).

Although the Union army had more artillery on the field, shortcomings in its organization allowed the Confederate army to have local superiority in close support artillery during the attacks of the I, XII and II Corps.  When I Corps attacked Jackson’s corps, it had 48 guns providing close support facing 68 Confederate guns.  The arrival of XII Corps brought 20 more Union guns onto this part of the battlefield (Naisawald).  II Corps had 40 guns (Hanson) to face the total of 72 Confederate guns in the vicinity of the Sunken Road (map Positions F and G) (Wise).

Sufficient artillery was often not available to support the Union infantry due to the poor artillery command system.  The XII Corps artillery appears to have followed the infantry onto the battlefield.  It assumed a defensive posture on the western edge of the East Woods.  No artillery was available for the lead division of II Corps when it advanced into the West Woods (Naisawald).  The remaining two divisions of the II Corps had, at most, one battery to provide close support during their fight at the Sunken Road.

In contrast to the Union artillery’s general inability to be at the right time and place to provide close support, the Confederate artillery was characterized by a high degree of agility.  For example, between the attacks of the I and XII Corps, Pelham positioned 13 artillery pieces on Hauser’s Ridge (map Position C).  This position could not be engaged by the Union counterbattery fire, yet Pelham was able to sweep the open ground between the North Woods and Dunker Church, thereby securing the Confederate left flank (Wise).

The Confederate artillery historian, Jennings Wise, calls Pelham’s action “one of those masterstrokes by a subordinate of highly developed initiative.” He further states, “…no one movement on either side bore a greater influence upon the final issue of the battle than did the advancement of Pelham’s group….This was a move on the chessboard, though perhaps by a pawn, which baffled the most powerful pieces of the enemy.”

A second example is S. D. Lee’s continuous repositioning of his battalion to engage Union forces.  He supported Jackson’s infantry during the I Corps attack (map Position D) and D.H. Hill’s division in the Sunken Road (map Position F) and fired on the IX Corps’ advance towards Sharpsburg (map Position I).  A third example occurred during IX Corps’ final assault (Luvaas and Nelson).  The Confederate extreme right (map Position J) consisted of a collection of guns from 10 different batteries and remnants of Toombs’ brigade (Wise).  Almost all these batteries had raced into position after refitting in Sharpsburg.  This thin line of metal held until A.P. Hill’s division arrived from Harper’s Ferry.

The single event that best contrasts the strength of the Confederate artillery and the weakness of the Union artillery in providing close support occurred at the Sunken Road.  At 1230, II Corps broke through the Confederate defensive position in the lane (Sears).  The Union army was on the verge of breaking the Confederate center.  The left was already exhausted by the attacks of I and XII Corps.  The right, depleted as divisions were sent to reinforce the left, was about to face the attack of IX Corps.

The defeat of Lee’s army and, possibly, the end of the war seemed at hand.  However, retreating Confederate infantrymen rallied around a single battery on the Piper farm overlooking the Sunken Road (map Position E). Other batteries arrived, increasing the number of Confederate guns to approximately 20 (Sears).

The Union infantry, completely without artillery, was unable to advance in the face of the Confederate artillery fire.  Major General Israel B. Richardson, the Union commander, pleaded for artillery support, but none could be provided.  Yet less than 1,500 meters to the north, seven inactive batteries with 44 guns were positioned along the edge of the East Woods (Sears).  Artillery historian L. Van Loan Naisawald calls this moment “the nadir in the history of American Artillery.”

Conclusion

The Union artillery employment during the battle is a classic example of the counterbattery mission.  The Confederate artillery employment demonstrates how initiative and superior fire support coordination can compensate for an interior artillery force.

The larger lesson lies in the development of each army’s artillery organization and command system before the battle.  Both armies confronted the same challenge: to employ large masses of artillery effectively and efficiently.

The Confederate leadership applied the lessons learned from previous campaigns and battles more readily.  They were quicker to divorce themselves from the outmoded practices of the past.  As a result, the Confederate artillery organization and command system made it more agile and responsive.  In turn, it was able to accomplish the close support mission better than the Union artillery during the Battle of Antietam and out performed a superior force.

Major Albert A. Mrozek, Jr., won Second Place in the U.S. Field Artillery Association’s 1992 History Writing Contest with this article.  He is an Assistant Professor of Military Science, Army Reserve Officer Training Corps at West Virginia University.  Major Mrozek’s other experience includes serving as the Commander of Headquarters and Headquarters Battery, 2^nd Battalion, 3^rd Field Artillery, 3^rd Armored Division in Germany; S1 of the same battalion; and battalion Fire Direction Officer and Assistant S3 for 3^rd Battalion, 8^th Field Artillery, 18^th Field Artillery Brigade, Fort Bragg, North Carolina.  Major Mrozek holds a Bachelor of Science from the US Military Academy at West Point and a Master of Public Administration from West Virginia University.     

The Army of the Potomac engages the invading Army of Northern Virginia at the Battle of Antietam, 16-17 September 1862.

This article was taken from: Mrozek, Jr., Major Albert A. "The Battle of Antietam: The Creation of Artillery Hell." (Field Artillery Magazine, August 1992) 30-34.  It is used with permission.

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