The Battle of Antietam

September 17, 1862 – The bloodiest day in American history occurred as the armies of Robert E. Lee and George B. McClellan fought to a standoff near Sharpsburg, Maryland, along Antietam Creek.

Gen. R.E. Lee, CSA and Maj Gen G.B. McClellan, USA | Image Credit:

Before dawn, Lee had arrayed his Confederate Army of Northern Virginia with Major General Thomas J. “Stonewall” Jackson’s men on the north (left), Major General James Longstreet’s Confederates in the center, and the small remainder of Lee’s command holding the south (right) until Jackson’s remaining division under General A.P. Hill could arrive from Harpers Ferry, 17 miles away.

Combat opened around 5:30 a.m. as Major General Joseph Hooker’s Federal corps advanced on the Hagerstown turnpike and attacked Jackson’s men in fog. The Federals hoped to seize the ground around the Dunker Church and turn the Confederate left.

Federals drove the first Confederate line out of the North Woods and into an area later known as the Cornfield. A Confederate counterattack led by General John Bell Hood pushed the Federals back to the Miller farm, with the lines surging back and forth over a dozen times.

Hooker later reported that “every stalk of corn in the northern and greater part of the field was cut as closely as could have been done with a knife, and the slain lay in rows precisely as they had stood in the ranks a few moments before.” Hooker was wounded himself and taken from the field, replaced by General George G. Meade.

Major General Joseph K. Mansfield’s Federal XII Corps then charged along Hooker’s left, moving through the East Woods and making a stand north of Dunker Church. Mansfield was shot in the chest after riding into a group of Confederates that he thought were Federals firing on their own men; he was replaced by General Alpheus Williams and died the next day.

The attack stalled until General John Sedgwick’s division from Major General Edwin V. Sumner’s corps attacked around 9 a.m. Confederates fired on them from three sides and sent them reeling. Sedgwick was wounded and out of active duty for several months.

During the fight, Lee shifted troops from his right to reinforce Jackson on the left. Meanwhile, McClellan’s plan to attack with overwhelming numbers turned into uncoordinated attacks that failed to reach their maximum impact. The Confederates held their ground, but Federals repelled a final counterattack. Fighting subsided around 10 a.m. with over 8,000 casualties inflicted in the northern sector of the field alone, including two Federal corps commanders.

A new fight soon erupted farther south, where General William French’s division of Sumner’s corps veered away from the fighting to the north and confronted Major General D.H. Hill’s 5,000 Confederates along a sunken road. French sent his troops against the Confederates one brigade at a time, and they were all repelled within an hour, sustaining 1,750 casualties out of 5,700 men.

Lee committed his last division in reserve, 3,400 men under Major General Richard H. Anderson, to Hill’s right, around 10:30. By that time, Major General Israel Richardson’s 4,000-man division under Sumner came up on French’s left. Federal troops eventually surged through a gap in the line caused by a Confederate officer mistakenly pulling out a regiment.

The Federals then opened a murderous enfilade fire on the defenders along the road. A sergeant of the 61st New York said, “We were shooting them like sheep in a pen. If a bullet missed the mark at first it was liable to strike the further bank, angle back, and take them secondarily.” The road was later called “Bloody Lane.”

The Federals were on the verge of breaking the Confederate line when Longstreet brought up artillery. A Confederate artillery shell wounded Major General Israel B. Richardson, who lingered 47 days before dying. This stalled Federal momentum, and the fighting soon ended in this sector. Some 5,600 total casualties were sustained along the sunken road from 9:30 a.m. to 1 p.m.

McClellan held some 20,000 Federals in reserve that could have been used to split Lee’s army in two. Major General George Sykes offered to lead these men in a charge through the Confederate center, but McClellan turned him down. The Federal commander missed a golden opportunity to destroy the Confederate army. McClellan wrote his wife that afternoon, “We are in the midst of the most terrible battle of the age. So far God has given us success but with many variations during the day.”

Action shifted to the weakened Confederate right, where Major General Ambrose E. Burnside’s IX Corps moved to cross Antietam Creek after various delays. Burnside directed his men to cross Rohrbach’s Bridge, even though Antietam Creek was only waist deep at various spots beyond Confederate range. The Federals were held up several hours at what became known as Burnside Bridge, allowing Lee to send more reinforcements to his left and center.

Federal attack on Burnside Bridge | Image Credit:

Meanwhile, other Federals struggled through brush to find Snavely’s Ford, about two miles downstream. They finally began wading across in early afternoon, around the time that the Confederates guarding the bridge were running low on ammunition. With Federals now on their flank, the Confederates withdrew after stalling Burnside’s main advance for over three hours.

Burnside prepared to pursue the Confederates, but he was delayed two hours by ammunition and supplies being funneled across the creek on the narrow bridge. This gave Lee time to reinforce his right. Burnside planned to turn Lee’s right and block Boteler’s Ford, Lee’s only escape back to Virginia. But by this time, A.P. Hill’s 3,000-man “Light Division” was arriving across the ford to bolster the flank. Hill’s men had marched since 7:30 a.m. and arrived just in time to save Lee’s army.

Hill slammed into the Federal left, prompting Burnside to order a withdrawal all the way back to Antietam Creek. When he called for reinforcements, McClellan responded, “I can do nothing more. I have no infantry.” But McClellan had V and VI corps under Major Generals Fitz John Porter and William B. Franklin in reserve. Fighting ended around 5 p.m. when McClellan called off the attacks.

Both sides sustained a combined total of 26,193 casualties in the most terrible single day of the war. The Federals suffered 12,469 losses (2,010 killed, 9,416 wounded, and 1,043 missing) out of about 75,000 effectives, while the Confederates lost 13,724 (2,700 killed, 9,024 wounded, and 2,000 missing) from roughly 40,000. Casualties were inflicted at the rate of about 2,200 per hour. The Federal Black Hat Brigade, recently nicknamed the “Iron Brigade,” lost 42 percent of its strength.

Medical personnel hurried to tend to the wounded; they turned nearby houses, churches, barns, and other buildings into makeshift hospitals. Local women volunteered as nurses. Doors were ripped from hinges to serve as operating tables. Surgeons worked nonstop through the night without washing their hands or instruments before going from one patient to another. A U.S. Sanitary Commission worker reported:

“Indeed there is not a barn, or farmhouse, or store, or church, or schoolhouse, between Boonesville, Sharpsburg, and Smoketown that is not gorged with wounded–Rebel and Union. Even the corn-cribs, and in many cases the cow stable, and in one place the mangers, were filled. Several thousands lie in open air upon straw, and all are receiving the kind services of farmers’ families and the surgeons.”

McClellan demonstrated his tactical ineptitude yet again by never committing more than 20,000 men to the fight at any one time. This helped Lee thwart the many Federal attacks. Antietam was one of the war’s few battles in which both commanders chose the battlefield and planned their tactics in advance. It was also the first battle that Lee directed from start to finish. Although the Confederates had not won, Lee skillfully directed reinforcements to points on the line where and when they were needed most, which prevented his army’s complete destruction.

Not only did the Confederates hold their ground against vastly superior numbers, but Lee even proposed to counterattack the next day. Lee believed an attack could succeed based on McClellan’s chronic lack of aggression. But after receiving his commanders’ reports and determining that he had no more than 30,000 men left, Lee decided that he could not renew the contest, especially with his back to the Potomac River. Even so, he defiantly held his ground and waited for McClellan to renew the battle on the 18th. McClellan characteristically declined.



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