Over 23,000 men fell as casualties in the 1-day Battle of Antietam, making it the bloodiest day in American history. The Union victory at Antietam resulted in President Abraham Lincoln issuing his Preliminary Emancipation Proclamation on September 22, 1862.
1862 – Turning Tides
The Battle of Antietam was one of the most important events of the American Civil War. Fought on September 17, 1862, Antietam was the bloodiest single-day battle in American history with over 23,000 casualties (men listed as killed, wounded, captured or missing) in roughly 12 hours. The battle ended the Confederate invasion of Maryland in 1862 and resulted in a Union victory.
It also led to President Abraham Lincoln issuing the Preliminary Emancipation Proclamation on September 22, 1862.In 1862, the American Civil War was entering its second year. In February, Union forces began a string of victories that threatened to destroy the young Confederacy. Union forces under Ulysses S. Grant took Forts Henry and Donelson in Tennessee and in April, those same forces defeated Confederate troops at the Battle of Shiloh. In the East, Union forces under the command of Major General George B. McClellan launched an attempt to capture the Confederate capital of Richmond, Virginia.
By the end of July, however, this tide of Union momentum had been slowed. On June 1, Confederate General Robert E. Lee took over the army defending Richmond. Two months later, after a series of bloody battles outside of the capital, Union forces began falling back. Washington lost faith in McClellan, and his army was recalled from Virginia in order to reinforce Major General John Pope’s army, which was moving against Richmond by an overland route. Yet, in the last week of August, Lee’s army had thoroughly defeated Pope, as well.
Momentum was now firmly in the hands of Lee and the Confederates.
The Maryland Campaign
In early September, Robert E. Lee decided to capitalize on his new momentum. On September 5, he began moving his army, the Army of Northern Virginia, across the Potomac River into Maryland. His primary goal was to defeat Union forces on loyal soil, thereby possibly bringing an end to the war and sealing Confederate independence.
A battlefield victory in Maryland could also convince England and France to recognize the Confederacy as an independent nation, a move that both countries were hesitant to make unless the Confederacy proved itself on the battlefield.Additionally, much of the war had been fought on Virginia soil thus far, and moving into Maryland would both allow Lee to feed his men from Maryland farms and harness support for the Confederate cause in that state. Maryland was a ‘Border State’ in the Civil War (a slave-holding state that stayed in the Union), and ultimately, the Confederacy wanted Maryland to secede and join their cause.
By September 9, all of Lee’s army was concentrated at Frederick, where he issued orders to split up his forces to capture the small town of Harpers Ferry, where a Union garrison of 12,000 soldiers was threatening the Confederate army.
While Lee’s army was invading Maryland, George McClellan was tasked with putting together a Union force to protect Washington and stop Lee. On September 7, after quickly reorganizing a defeated and demoralized army, McClellan began moving into Maryland to stop the Confederate invasion.
By the 14th of September, McClellan had caught up with part of Lee’s divided force and the Battle of South Mountain was fought, resulting in a Union victory. The next day, another piece of the Confederate army was able to force the surrender of Harper’s Ferry, and Lee began to reunite his army at Sharpsburg, Maryland, near Antietam Creek.
September 17, 1862
The Battle of Antietam began early on the morning of September 17, 1862. Union forces of the First and Twelfth Corps were sent across Antietam Creek the day before by McClellan in an attempt to attack the Confederate left flank (the flank is the side of an army or battle line). From 6 am to 10 am, these forces were engaged with Confederates under Major General Thomas ‘Stonewall’ Jackson in a 24-acre cornfield, now known simply as The Cornfield.
These were the fiercest hours of the battle; over 8,000 casualties fell during this time. As Union General Joseph Hooker later wrote, ‘It was never my fortune to witness a more bloody, dismal battlefield.’ During the first hour of the fighting in the Cornfield, the slaughter was so intense that one man fell, was killed, or wounded every second.
By 10 am, Union forces had taken the Cornfield, but the Confederates remained on the field.Just as the fighting in the now infamous Cornfield was winding down, the Union Second Corps, commanded by Major General Edwin V. Sumner, began moving onto the field.
One division of the corps pushed due west into an area known as the West Woods; in this woodlot, these 5,000 Union soldiers were hit by a severe flank attack, losing almost 50% of their strength in half an hour.While disaster struck in the West Woods, the other two divisions of the Second Corps assaulted an old sunken farm road in the middle of the battlefield, now known as Bloody Lane. From 10 am until 1 pm, Union forces struggled to take this position and thousands more were killed, wounded, or missing. By 1 pm, Union forces had taken the road, breaking a hole in the Confederate lines. However, because of exhaustion and heavy casualties, these Union troops were not able to advance any further. By the early afternoon hours of September 17, about 17,000 Union and Confederate soldiers had fallen as casualties at Antietam.
While the action thus far had taken place on the Northern end of the field, McClellan also wanted to attack the Confederate right flank to the south. Starting at 9:30 am, the Union Ninth Corps, commanded by Major General Ambrose Burnside, began advancing against the Confederate flank. However, Burnside first had to cross Antietam Creek at the sight of the Lower Bridge, now known as Burnside Bridge. For several hours, determined and outnumbered Confederates stymied Union efforts to cross the creek.
At 1 pm, Union forces finally took the bridge.
Next, Burnside launched a massive assault against the outnumbered and exhausted Confederate right flank. By 4 pm, Burnside’s troops were coming close to turning Lee’s flank and possibly trapping and crushing the Confederate army in Maryland. However, at the last minute, as though scripted in a Hollywood movie, Confederate reinforcements arrived on the field and stopped the Union assault.
At the end of the day on September 17, 1862, there were over 23,000 casualties, making it the bloodiest day in American history.
For 12 hours, there was one casualty every two seconds. Robert E. Lee’s Army of Northern Virginia had lost over 10,000 men, or one out of every four soldiers. For most of the day on the 18th, both armies sat in their battle lines from the day before, too exhausted to attack any further.Because of these losses, Lee had no choice but to retreat back to Virginia on the evening of September 18.
The battered Union forces launched a pursuit and a small battle was fought at Shepherdstown, Virginia, (now West Virginia) on the 19th and 20th of September, but no other major action would occur. George McClellan’s Army of the Potomac stayed in Maryland for several weeks after the battle, resting and refitting for another battle. Because of this delay, McClellan was removed from command and Ambrose Burnside took his place.
Early in September 1862, when Abraham Lincoln learned of the Confederate invasion of Maryland, he decided that, if the Union army successfully stopped Lee, he would issue his Preliminary Emancipation Proclamation. Lincoln had decided to issue the measure in July 1862, but he wanted to wait for a victory so that the proclamation would not look like a desperate move by a government on the verge of losing the war.
Antietam was the victory he had been waiting for and on September 22, 1862, Lincoln issued his Preliminary Emancipation Proclamation.The proclamation declared that on January 1, 1863, when the final version was signed, all slaves in those states then in rebellion against the Federal government would be ‘then, thenceforward, and forever free.’ It also opened the door for African Americans to serve in the Union army during the Civil War. Eventually, over 200,000 African Americans wore the Union uniform, a major boost in manpower that helped to win the war for the Union.
The Battle of Antietam occurred on September 17, 1862 near Antietam Creek in Maryland.
It was one of the bloodiest battles of the American Civil War and remains the single bloodiest day in American history with over 23,000 casualties. President Abraham Lincoln used the Union victory at Antietam to make his Preliminary Emancipation Proclamation on September 22, 1862. The final version of the proclamation was signed and went into effect on January 1, 1863, thus allowing African Americans to fight as part of the Union and eventual win the Civil War.