September 17, 1862

The battle of the American Civil War at Antietam Creek is the bloodiest day in U.S. History.

Altogether, some 23,000 soldiers died.
This is a big number, but it gets bigger when you put it into context.

The American casualties on D-Day amount to roughly 2,500 — one-ninth of those sustained at Antietam.
The battle ended more American lives than the Revolutionary War, the War of 1812, the Mexican War, and the Spanish-American War combined.

Twenty-three thousand. Let that sink in.

Background

General Lee was a big man in the Confederate army.

Taking Bull Run had given him some momentum. It had been a stunning victory and the Union soldiers were still in chaos. A week after leaving Bull Run he decided to take his men North.

He knew that moving into Maryland would relieve Virginia of Union occupation and that the enemy would have to mirror his movements the whole way, taking up defensive positions along Washington and Baltimore. Second, much of Maryland was unharvested virgin land and autumn was approaching: taking up residence there before winter would ensure hearty rations for the cold. He also hoped to win the favor of Marylanders and lead them to secede from the Union to the southern cause.

However, his most important reason for taking his men north was to gain the attention of the French and English. He hoped that leading his army to another large victory would earn the Europeans' diplomatic recognition and bring them into the fray on his behalf.

On September 4 1862 the Virginian army crossed the Potomac River north of Leesburg and set up camp. Two days later Stonewall Jackson led his battalion of 5,000 into the north side of Frederick. Lee brought in his remaining force of 40,000 shortly thereafter.

On arriving in town, Lee composed his Proclomation to the People of Maryland, inviting them to join his cause. He issued strict orders to his men not to pillage the city, instructing them instead to buy as many supplies as they could from the stores in town. Unfortunately for Lee, the arrival of his bustling army and their diplomacy did nothing to win the Marylanders' approval; they were polite but had no intention of siding with the South. Faced with this new obstacle, Lee reworked his plans: he divided his army into four battalions and dispatched one under Jackson southwest to the Federal garrison at Harpers Ferry, and the other three under General James Longstreet to Boonesboro and Hagerstown, roughly 25 miles northeast over the Chatoctin and South mountain Ranges. Once he rejoined his men in Hagerstown, Lee laid down plans to exploit the mountains for protection on the right flank while moving northeast along the Pennsylvania Rail Line to Harrisburg. On the morning of September 10 Lee's army divided.

As smoothly as the operations had gone so far, Lee's plan was undermined by several unforseen events. First, Union General George McClellan regrouped his own army in a few days rather than the expected several weeks and entered Fredrick two days after Lee left. Second, the soldiers at Jackson's destination, Harpers Ferry, had received orders to wait for reinforcements rather than retreat. Third and most embarrassing, General Lee left written records of his plans at a derelict campsite and they were discovered by a Federal private, wrapped in three cigars, the day after the Union arrived in Frederick.

Immediately, Lee compensated for his divided army by sending forces to block the passes over South Mountain, hoping to buy enough time to consolidate his men around Sharpsburg, southwest of Boonsboro, near the Antietam Creek. Meanwhile, McClellan gathered his 85,000 men on the east bank.

Miller's Cornfield

Lee placed cannons on the ridge east of Sharpsburg in front of Dunker Church, filled the firing gaps with infantry men, and dispatched a handful of Georgia sharpshooters to the lower bridge. By that evening, McClellan had 60,000 men — double Lee's available forces — prepared to attack.

The next morning, McClellan let loose the artillery.

Union troops wading through Miller's Cornfield north of town encountered a surprise attack from Jackson. McClellan withdrew his men and trained cannons on the field; one Union officer said later that every stalk on the property was severed and that the slain confederate forces lay neatly as though still in ranks. McClellan sent his men through a second time, driving the confederates back with roughly an hour of violent shelling, but Jackson received reinforcements and at about 7am was able to drive the Federals back again.

According to some sources the corn field changed hands fifteen times that day. Union troops under General Joseph Mansfield regrouped and stormed Miller's field again, but this time the battle devolved into both armies standing there firing at one another from less than 200 yards apart until, according to New York Federal soldier Isaac Hall, "The lines melted away like wax."

Meanwhile, Union General John Sedgwick led his division into the woods to the west, hoping to overtake the Confederate left flank. To his dismay he was struck by enemies arriving from other parts of the field; he lost half his division in fifteen brutal minutes of point-blank fire.

As the day edged into early afternoon some 10,000 men lay dead at the Battle of Antietam.

Bloody Lane

Bloody Lane was an 800-yard path separating the nearby Roulette and Piper farms, deeply rutted by years of wear from passing grain wagons. Protected from Union fire and with a clear line of vision, five brigades under General D.H. Hill took refuge in the trench and repelled four separate Union charges over the space of three and a half hours.

Union troops aided by the French paraded before Bloody Lane, firing at whatever they could hit. By early afternoon almost 6,000 men had died and been wounded along the half-mile stretch of road.

Finally, the New York 61st and 64th regiments worked their way up around the eastern end of the sunken road and sent a storm of lead into the Confederate ranks. Roughly 300 Rebels threw down their arms and surrendered right then. A Confederate officer misinterpreted an order and pulled his men out of the trench; many of the soldiers ran all the way to the far side of Sharpsburg.

Seeing that the end was in sight, General Lee rushed twenty cannons to the Piper farm. Meanwhile some 200 Rebels submitted a weak counterattack at Bloody Lane but were promptly squashed.

Then General McClellan made one of the biggest mistakes in military history.

Lee was a sitting duck. To have overrun him then would have destroyed the nerve center of the Confederate army and ended the war, but instead of regrouping his fresh reserves for an attack on the cannons, McClellan pulled back.

The Confederacy would live to fight for three more years.

The Burnside Bridge

Since that morning, the Georgia sharpshooters Lee had sent to the lower bridge had been holding back repeated Union charges, hiding behind boulders and trees on the steep bluff overlooking the creek. Union General Ambrose Burnside's troops weren't able to cross the bridge until 1pm; after taking two hours to rest and reload they pushed their way toward Sharpsburg.

Sharpsburg's streets were clogged with retreating rebels. Then in the late afternoon General Hill's division arrived from a 17-hour march from Harpers Ferry and immediately attacked the Union's vulnerable left flank. Burnside was forced to return his troops to the bluffs near the creek; the combined carnage at the lower bridge — known now as "The Burnside Bridge" — and Hill's counterattack claimed 3470 lives, two-thirds of them Union.

Even with Hill's surprise counterattack, the Rebel forces were all but destroyed. McClellan had 20,000 fresh men in reserve, twice as many as he needed to overtake Lee and end the war.

And, again, he relented.

The Battle of Antietam was over.

Twenty Dead Generals

The next day Union and Confederate leaders came to an informal truce and started to remove their wounded and dying from the battlefield. That evening Lee started to withdraw his men back across the Potomac.

Lee's failed campaign into the north probably caused the British to postpone their recognition of the Confederate government. Similarly, Abraham Lincoln took the opportunity presented by Lee's defeat to issue the Emancipation Proclomation, which broadened the Union's purpose to end human bondage on American soil in addition to preserving its own borders.

The Union lost 12,410 men, the Confederacy 10,700. It's said that one in four who fought at Antietam died.

Incredibly, twenty generals died from wounds sustained at the battle of Antietam — eighteen at the main skirmish near Sharpsburg, two at the improvised garrison on South Mountain. The symmetry is unsettling: each side lost precisely ten.

Again but Quicker

September 4–6 — General Robert E. Lee begins a campaign to take the Union, consolidating his battallion in Frederick, Maryland and hoping to win the favor of the people with cofidence and diplomacy. The ploy fails.

September 10 — Lee finalizes a new plan of attack and deploys his army for a surprise flanking on Union forces still shellshocked from Bull Run.

September 12 — Union General George McClellan recovers his army weeks faster than expected and leads his men into Frederick.

September 13 — A Union private discovers Lee's Special Order 191 in an abandoned Confederate campsite, detailing the general's plan to surprise Union forces by flanking along the mountains.

September 14 & 15 — General Lee promptly regroups his men, setting up barriers in the mountain passes and consolidating the rest of his forces near Antietam Creek on the outskirts of Sharpsburg.

September 16 — In the evening McClellan arrives at the opposite bank with his own force of 85,000 and prepares for battle.

September 17 — McClellan opens artillery fire and the Battle of Antietam begins.

Sources

Grolier Encyclopedia of Knowledge Vol. 2. Grolier: Danbury. 1991. 28.

US National Park Service
http://nps.gov/anti/

Shotgun's Guild Press
http://www.civilwarhome.com/antietam.htm

Collector's Net
http://www.collectorsnet.com/cwtimes/antietam.htm

Harper's Brother's American History Volume I, reproduced by "Son of the South" Web site
http://www.sonofthesouth.net/leefoundation/battle-antietam.htm