September 17, 1862 was a bad day for both sides. The Confederate Army led by Robert E. Lee was marching north in an attempt to invade Maryland. The Union Army met the Confederates at Antietam Creek in Sharpsburg, Maryland. Stonewall Jackson and his men fought back throughout the day across open fields, creeks, and ravines. The following day, reinforcement of Union and Confederate troops arrived to fight in the bloodiest one day battle in U.S. history. Multiple back-and-forth clashes between both sides lead to more than 22,000 total killed, wounded, missing, or captured soldiers.
The battle was a military draw but the Union Army had reasons to feel victorious. The battle was part of intent by the confederacy to invade the north.
Confederate soldiers were treated across the Potomac River back into Virginia. The Union chose not to follow. The invasion of the north had been stopped. News of the victory strengthened the Union Army and lead to the creation of the Emancipation Proclamation.