The Bloodiest Day

The Overlook

By Tom Clavin

“The Overlook” appears every Thursday at An overlook is usually a place from which one can see in many if not all directions, including where one has been and where one is going. If you enjoy the column, please "like" it and let me know what you think by commenting (check out previous ones while you're at it).  Likes, comments, and shares help with author discoverability on, and all support is appreciated.Don't forget to hit the ‘Subscribe’ button – it’s free!

          The Battle of Antietam, which took place 159 years ago this week, is often referred to as the bloodiest day in American history. And it was. However, that easy label tends to overshadow the several ways this particular battle was significant in the Civil War. Some historians even think this battle was more pivotal than Gettysburg 10 months later.

          To the particulars, beginning with an intriguing prelude. On September 13, 1862, just outside Frederick, Maryland, two Union soldiers, John Bloss and Burton Mitchell, found an abandoned Confederate camp. That the Rebs were in Maryland was interesting enough, but the real surprise was the discovery of three cigars wrapped in a piece of paper. That paper turned out to be Special Order 191, which was Gen. Robert E. Lee’s strategy for attacking the North. Especially beneficial to the Union Army was the information that Lee had divided his Army of Northern Virginia into five groups, making each one more vulnerable to attack.

          This cigar wrapping should have been a godsend to Gen. George B. McClellan, The Union’s top general and commander of the Army of the Potomac. But true to form, he dithered and took 18 hours to mobilize his forces. Meanwhile Lee, who had learned of the Yankee discovery of Special Order 191, gathered his groups back together. An enormous Union opportunity had been squandered.

          Over the next several days the armies inched toward each other. Lee hoped that a successful invasion of the North would be a knockout blow after 19 months of war. On September 17, he had his chance at Antietam Creek in Maryland. The Union needed a victory too. President Abraham Lincoln had written the Emancipation Proclamation, but after several recent Union losses, including the Second Battle of Bull Run, he needed some good news to strengthen his position of freeing slaves. Politically, in less than two months there would be midterm elections and the Republican Party’s majority in Congress might not survive them. Frustrated with Lincoln’s policies and the course of the war, Democrats had launched an anti-war campaign, hoping to take power and possibly negotiate peace with the South. A definitive Confederate victory at this crucial juncture could help secure the Confederacy once and for all. Another consequence of victory could be Great Britain and/or France throwing their support to the South.

After Lee thwarted the plan of McClellan to lay siege to Richmond in the Peninsula Campaign in the spring and summer of 1862, McClellan retreated. Hoping to take advantage of the Union’s low morale and seeming ineptitude, Lee chose to push his army north across the Potomac and into Maryland where they soon occupied the town of Frederick. On September 9, Lee had issued Special Order 191 defining his “Maryland Campaign.” His plan included sending his divided forces Boonsboro and Hagerstown in Maryland and Harper’s Ferry and Martinsburg in West Virginia.

          But four days later, McClellan had Lee’s plans in his hands. He reportedly exclaimed, “Here is a paper with which, if I cannot whip Bobby Lee, I will be willing to go home.” But his lumbering army did not move fast enough and Lee had time to reunite its units.

On September 14, at the base of South Mountain near Sharpsburg, Confederate Generals D.H. Hill’s and James Longstreet’s units encountered Union resistance and sustained heavy casualties. Lee planned to retreat to Virginia but changed his mind after hearing that Confederate General Thomas “Stonewall” Jackson had captured Harper’s Ferry. Instead, Lee ordered his army to regroup at Antietam Creek near Sharpsburg.

The Battle of Antietam began at dawn on September 17, 1862, as the fog lifted. Longstreet’s and Hill’s units formed the Confederate right and center flanks to the west of Antietam Creek, while Jackson’s and Gen. John G. Walker’s units formed the Confederate left flank. All of Lee’s troops were worn out and hungry, and many were sick. They watched and waited as McClellan’s army assembled along the creek’s east side. Union forces outnumbered Confederates by two to one, although McClellan thought Lee’s forces were much larger. Troops from both sides faced off across a 30-acre cornfield.

Union troops fired first at the Confederate’s left flank and the carnage began. Confederate troops ferociously fought off offensive after offensive to prevent being overrun, turning the cornfield into a massive killing field. Just eight hours in, there were over 15,000 casualties. Near the center of the battlefield, another site of slaughter was a farm lane known as the “Sunken Road,” where Hill’s division of approximately 2600 men had piled fence rails along the road’s embankment to fortify their position against Union Major General William H. French’s 5500 approaching troops. When French’s troops arrived, fighting ensued at close range. Three hours later, Union troops had pushed the Confederates back and over 5000 men were either dead or injured. The fighting was so gory Sunken Road earned a new name: Bloody Lane.

For more than three hours, fewer than 500 Confederate soldiers held Lower Bridge against multiple assaults by Union General Ambrose Burnside’s Ninth Corps. After Burnside’s troops finally took the bridge and had the Confederate right flank in sight, Confederate reinforcements arrived and pushed them back.

As night fell, according to an account on, “thousands of bodies littered the sprawling Antietam battlefield and both sides regrouped and claimed their dead and wounded. Just twelve hours of intense and often close-range fighting with muskets and cannons had resulted in around 23,000 casualties, including an estimated 3650 dead.”

The next day, Lee began the painstaking job of moving his ravaged troops back to Virginia. While this was going on, McClellan, apparently stunned by the number of casualties, did nothing. Despite having a numerical advantage, he allowed Lee to retreat without firing a shot. He had, at least, prevented a Confederate win on Union soil.

His boss was not so sanguine. President Lincoln thought McClellan missed a great opportunity to kick the Army of Northern Virginia while they were down and potentially end the war. After the young and hesitant general repeatedly refused Lincoln’s order to pursue Lee’s retreating troops, the President fired him. Gen. Burnside replaced McClellan, who two years later would unsuccessfully challenge Lincoln in the presidential election.

Many military historians consider the Battle of Antietam a stalemate. Even so, the Union claimed victory. And keeping Confederates in their southern box enabled President Lincoln to finally release his Emancipation Proclamation. Ironically, it did not free slaves in Maryland because it only applied to slaves in rebel states. Still, it endorsed the idea that the war was not just about states’ rights but also ending slavery.

The Union’s claim of victory at Antietam helped the Republicans hold the House in the mid-term elections. It also ended any hope of France and Great Britain acknowledging the Confederacy and coming to its aid. This further isolated the Confederacy and made it harder for it to re-supply its troops and citizens. The bloodiest day in American history had its bright spots and the Union fighters, at least, had not died in vain.

Tom Clavin is the bestselling author/co-author of 18 books, including the forthcoming Lightning Down: A World War II Story of Survival, to be published by St. Martin’s Press on November 2. To pre-order, please go to your local bookstore or to,, or (Psssst: It’s really good.)