The 15th Massachusetts Infantry was mustered into service on July 5th, 1861 and first saw significant action in the Battle of Ball’s Bluff in October of that year. The regiment was assigned to the 1st Brigade of the 2nd Division of the Union 2nd Corps in March of 1862, and maintained that designation throughout the remainder of its service. The unit saw action in the Peninsular Campaign in the summer of 1862, particularly at the Battle of Fair Oaks.
On September 17th, 1862, the Army of the Potomac under Major General George McClellan and the Army of Northern Virginia under General Robert E. Lee clashed at Antietam Creek near Sharpsburg, Maryland in the Battle of Antietam. The 2nd Corps was under the command of Major General Edwin Sumner with Major General John Sedgwick commanding the 2nd Division. Sedgwick’s division entered the battlefield at the East Woods and advanced to the West Woods, north of the Dunker Church. The Federal 1st and 11th Corps had already participated in extensive fighting in the area, and the 2nd Corps was sent in as reinforcements. Sedgwick’s division was deployed in three lines by brigade. The 1st Brigade, consisting of the 15th Massachusetts (plus one company of Massachusetts Sharpshooters that was assigned to it), 1st Minnesota, 82nd New York, and 34th New York Infantry Regiments under the command of Brigadier General Willis A. Gorman, led the way and advanced toward the West Woods. Due to a mix up, the 34th New York became separated and advanced south instead of west, leaving just three regiments in the line.
The brigade advanced into the West Woods and became engaged with Virginia and Georgia regiments under Brigadier General Paul J. Semmes and Brigadier General John R. Jones. The 15th Massachusetts was on the left flank of the line, and while it was fighting Confederates in its front, it also began taking fire from the 59th New York Infantry in the second Union brigade line directly behind it. Intervention from General Sumner finally stopped it, but not before the 15th suffered some friendly fire casualties.
While heavy fighting continued in its front, the 15th also had to contend with an attack on its left flank and rear from Brigadier General Jubal Early’s Virginians and Brigadier General William Barksdale’s Mississippi troops. Taking fire from three sides, the 15h Massachusetts and much of the rest of Sedgwick’s division retired to the north.
Lieutenant Colonel John W. Kimball commanded the 15th Massachusetts at the Battle of Antietam and filed this after action report:
HEADQUARTERS FIFTEENTH REGIMENT, MASS. VOLS.,
Camp near Sharpsburg, September 20, 1862.
CAPTAIN: I have the honor to report that on Wednesday, 17th instant, at 7 o’clock a.m., I was ordered to hold my command in readiness to move at a moment’s notice. At 7.30 o’clock we took up our line of march with 582 muskets, including First Company Andrew Sharpshooters, Capt. J. Saunders, attached to this command, being the third regiment in, the brigade line. We moved it a direct line toward the ground held by the forces under command of General Hooker, fording, in the march, Antietam Creek. On reaching the field, a line of battle was formed, in which my command occupied the position of third regiment of the first line. We then moved forward in line under a severe artillery fire about one mile over the ground gained by General Hooker, passing fences, fields, and obstacles of various descriptions, eventually occupying a piece of woods, directly in front of which, and well covered by the nature of the ground, field of grain, hay-stacks, buildings, and a thick orchard, were the enemy in strong three.
At this time we were marching by the right-oblique, in order to close an interval between my command and that of Colonel Hudson, Eighty-second New York Volunteers, and as we gained the summit of a slight elevation my left became hotly engaged with the enemy, covered as before mentioned, at a distance of not more than 15 yards. A section of the enemy’s artillery was planted upon a knoll immediately in front of and not more than 600 yards distant from my right wing. This was twice silenced and driven back by the fire of my right wing, concentrated upon it. The engagement lasted between twenty and thirty minutes, my line remaining unbroken, the left wing advancing some 10 yards under a most terrific infantry fire.
Meanwhile the second line of the division, which had been halted some 30 or 40 yards in our rear, advanced until a portion of the Fifty-ninth Regiment New York Volunteers, Colonel Tidball had closed upon and commenced firing through my left wing on the enemy. Many of my men were by this maneuver killed by our own forces, and my most strenuous exertions were of no avail either in stopping this murderous fire or in causing the second line to advance to the front. At this juncture General Sumner came up, and his attention was immediately called by myself to this terrible mistake. He immediately rode to the right of the Fifty-ninth Regiment, ordered the firing to cease and the line to retire, which order was executed in considerable confusion.
The enemy soon appeared in heavy columns, advancing upon my left and rear, pouring in a deadly cross-fire on my left. I immediately and without orders ordered my command to retire, having first witnessed the same movement on the part of both the second and third lines. We retired slowly and in good order, bringing off our colors and a battle-flag captured from the enemy, reforming by the orders of General Gorman in a piece of woods some 500 yards to the rear, under cover of our artillery. This position was held until I was ordered to support a battery planted upon the brow of a hill immediately in our rear, the enemy having opened again with artillery. His fire being silenced, the position was held throughout the day.
I desire to say that my entire regiment behaved most gallantly during the engagement, evincing great coolness and bravery, as my list of casualties will show. Although suffering terribly from the fire of the enemy, it was with great surprise that they received the order to retire, never entertaining for a moment any idea but that of complete success, although purchased at the cost of their lives. The order forbidding the carrying wounded men to the rear was obeyed to the very letter.
Of my line officers, without exception, I cannot speak in too high praise. They were all at their posts, bravely and manfully urging on their men, and equally exposed with them. Those wounded refused all assistance, ordering their men to return to the ranks and do their duty.
I desire to call your particular attention to Major Philbrick and Adjutant Hooper. They were with me during the entire engagement in the thickest of the fight, receiving and executing my orders with great coolness and promptitude.
I herewith append a list of the casualties in the late engagement. Officers killed: Capt. C. S. Simonds, Capt. J. Saunders, First Lieut. R. Derby, First Lieut. William Berry, First Lieut. F. S. Corbin. Officers wounded: Capt. W. Forehand, slight; Capt. G. C. Joslin, severe; Capt. A. Bartlett, slight; First Lieut. Thomas J. Spurr, severe; First Lieut. L. H. Ellingwood, severe; Second Lieut. W. Gale, slight; Second Lieut. A. J. Bradley, slight. Enlisted men killed, 60; wounded, 238 missing, 38. Officers killed and wounded, 12. Enlisted men killed, wounded, and missing, 336. Total, 348.
I have the honor to be, very respectfully, your obedient servant,
JOHN W. KIMBALL,
Capt. J. W. GORMAN,
As noted by Kimball, the regiment took heavy losses in what was a narrow Union victory in the bloodiest single day battle of the Civil War. Another later tally of the 15th’s casualties listed 65 killed, 255 wounded, and 24 missing or captured for a total of 344. By either account, the 15th Massachusetts suffered the highest number of Union casualties of all Federal regiments engaged that day. The 1st Minnesota, one of the 15th’s fellow brigade regiments, would go on and suffer 82% casualties at Gettysburg about 10 months later.
The 15th Massachusetts continued to see extensive fighting in the eastern theatre battles and campaigns until the regiment was mustered out in July 1864.
A Compendium of the War of the Rebellion by Frederick H. Dyer
Landscape Turned Red: The Battle of Antietam by Steven W. Sears
Official Records of the Union and Confederate Armies in the War of the Rebellion. Series I, Volume XIX, Part 1.
Regimental Losses in the American Civil War 1861-1865 by William F. Fox