A misty rain shrouded Antietam Creek as Pvt. David L. Thompson and other footsore soldiers from the 9th New York Infantry took their places on the Union line and unrolled their blankets. It was Sept. 16, 1862, a night marked by the sputtering fire of nervous pickets, the cursing of men tripping over objects in the dark (including a regimental dog), and waves of panic.
“We sat down and watched for a while the dull glare on the sky of the Confederate campfires behind the hills,” Thompson wrote. “We were hungry, of course, but as no fires were allowed, we could only mix our ground coffee and sugar in our hands and eat them dry. ... There was something weirdly impressive yet unreal in the gradual drawing together of those whispering armies under cover of the night—something of awe and dread.”
Two great armies were steeling themselves for what would become the deadliest one-day battle in American history. That 12-hour fight would change the course of the war, determine the fate of 4 million slaves and shock the public. Thanks to some of the first—and still most haunting—battlefield photographs in history, people would see the reality of the fratricide that until then had been a distant abstraction.
North and South fought in the open at close quarters—usually no more than 300 yards apart—with no protective earthworks to soften the blows. Gen. Robert E. Lee, leading thousands of tattered, battle-hardened Confederate troops into enemy territory for the first time, tried for a desperate knockout punch that would bring the two-year-old conflict to a swift conclusion. Maj. Gen. George B. McClellan, charged with fending off the Confederate invasion threatening the capital in Washington, summoned the largest army yet to face Lee’s forces and tried to pin his adversary at Antietam, with the Potomac River at Lee’s back.
The clash was one of the worst days in a long war known for its carnage. Because the literacy rate in both armies was quite high—above 90 percent—the survivors wrote letters and diaries detailing their experiences, and we have an excellent record of what transpired at Antietam. Time has softened the horror, but even today the photographs and remembrances of those who were there offer a glimpse of a national tragedy written in smoke and blood.
The morning of Sept. 17 opened with a tremendous crash as opposing batteries traded blows across the creek. Maj. Gen. Joseph “Fighting Joe” Hooker and some 8,600 men of the Union First Corps came boiling out of the woods about 6 a.m. and headed for Dunker Church. The squat white building marked the northern end of the Confederate line, held by Maj. Gen. Stonewall Jackson’s troops. “The Federals in apparent double battle line were moving toward us at charge bayonets, common time,” wrote a veteran of the Stonewall Brigade, “and the sunbeams falling on their well-polished guns and bayonets gave a glamour and a show at once fearful and entrancing.”
To reach the church, Hooker’s troops had to cross open ground, plunge into a thickly planted cornfield and emerge on the far side. But the cornfield erupted in a torrent of fire from Confederates hidden among the stalks.
As the first of Hooker’s troops fell in the corn, others poured in to replace them, scrambling around the dead and driving for the church. “Men, I can not say fell; they were knocked out of the ranks by dozens,” wrote Maj. Rufus Dawes of the 6th Wisconsin Regiment. “But we jumped over the fence, and pushed on, loading, firing and shouting as we advanced. There was, on the part of the men, great hysterical excitement, eagerness to go forward and a reckless disregard of life.” They pursued Jackson’s troops toward Hagerstown Pike, riddling them from behind as the Confederates tried to clamber over the roadside fences.
To stiffen his lines, Jackson summoned Brig. Gen. John Bell Hood’s troops, who were cooking the first hot meal they had eaten in days. Hood’s men put their bread aside, took up muskets, and streaked toward the battle, screeching as they went. “I have never seen a more disgusted bunch of boys and mad as hornets,” a soldier from Hood’s 2,300-man division recalled. The hungry Rebels smashed into Hooker’s forces, mowing down Union troops “like a scythe running through our line,” one Federal survivor wrote. Surging across the cornfield, Hood’s counterattack regained most of the bloody ground lost earlier that morning—with more than 60 percent of his men dead, wounded, or missing. When Hood returned from the front, trailed by a remnant of his command, someone asked where his troops were. “Dead on the field,” he said.
Two other Union corps fed fresh soldiers into the fight as Lee desperately stripped other parts of his line to meet each new thrust. By 10 a.m., the cornfield had changed hands 15 times. “Every stalk of corn in the greater part of the field was cut as closely as could have been done with a knife,” Hooker recalled, “and the slain lay in rows precisely as they had stood in their ranks a few moments before.” Riding among his men on a big gray horse, the general made an easy target. He was shot in the foot and put out of action that morning.
He was one of almost 10,000 casualties from the opening hours of fighting; another was a recent Harvard graduate, Capt. Oliver Wendell Holmes Jr. of the 20th Massachusetts, shot through the neck and left for dead on the field. Holmes recovered, finished the war with distinction, and became a Supreme Court justice. But he admitted that after Antietam, “the world never seemed quite right again.”