The Battle of Antietam was a battle of the American Civil War fought on September 17, 1862, between Confederate Gen. Robert E. Lee's Army of Northern Virginia and Union Gen. George B. McClellan's Army of the Potomac

 The Battle of Antietam was a battle of the American Civil War fought on September 17, 1862, between Confederate Gen. Robert E. Lee's Army of Northern Virginia and Union Gen. George B. McClellan's Army of the Potomac

The Battle of Antietam was a battle of Antietam. 

The American Civil War fought on September 17, 1862, between Confederate Gen. Robert E. Lee's Army of Northern Virginia and Union Gen. George B. McClellan's Army of the Potomac near Sharpsburg, Maryland, and Antietam Creek. Part of the Maryland Campaign, it was the first field army–level engagement in the Eastern Theater of the American Civil War to take place on Union soil. It remains the bloodiest day in American history, with a combined tally of  dead, wounded, or missing

Although the Union Army suffered heavier casualties than the Confederates, the battle was a major turning point in the Union's favor

The Dead Of Antietam, 1862

It was at Antietam, the blood-churning battle in Sharpsburg, Md., where more Americans died in a single day than ever had before, that one Union soldier recalled how “the piles of dead … were frightful.” The Scottish-born photographer Alexander Gardner arrived there two days after the September 17, 1862, slaughter.

He set up his stereo wet-plate camera and started taking dozens of images of the body-strewn countryside, documenting fallen soldiers, burial crews and trench graves.
Gardner worked for Mathew Brady, and when he returned to New York City his employer arranged an exhibition of the work. Visitors were greeted with a plain sign reading “The Dead of Antietam.” But what they saw was anything but simple.
Genteel society came upon what are believed to be the first recorded images of war casualties. Gardner’s photographs are so sharp that people could make out ­faces.

The death was unfiltered, and a war that had seemed remote suddenly became harrowingly immediate. Gardner helped make Americans realize the significance of the fratricide that by 1865 would take more than 600,000 lives.

For in the hallowed fields fell not faceless strangers but sons, brothers, fathers, cousins and friends. And Gardner’s images of Antietam created a lasting legacy by establishing a painfully potent visual precedent for the way all wars have since been covered