Wednesday, September 17. The bloodiest single day of the war occurred at the Battle of Antietam near Sharpsburg, Maryland. General Robert E. Lee’s outnumbered Confederate Army of Northern Virginia assembled along Antietam Creek to meet the attack by General George B. McClellan’s Federal Army of the Potomac. The first wave of assaults took place on the Confederate left against General Thomas “Stonewall” Jackson’s corps in the woods, the cornfield, the Bloody Lane, and the Dunkard Church. Federal gains were small and costly. The battle then shifted to the center of the Confederate line, with uncoordinated Federal attacks again achieving little. Finally, the battle moved to the Confederate right, where Federals crossing a bridge finally broke through and headed for Sharpsburg. However, they were halted by General A.P. Hill’s “Light Division” arriving from Harpers Ferry to save Lee’s army. McClellan’s piecemeal attacks and failure to use all his reserves also helped save the Confederate army from destruction. The battle ended when McClellan disengaged, making it a draw. Total casualties for this single day were estimated at over 26,000 killed, wounded, or missing. In Kentucky, a Federal garrison of over 4,000 men surrendered to General Braxton Bragg’s Confederates. Federal General Ormsby M. Mitchel assumed command of the Department of the South, stationed along the southeastern coast.
Thursday, September 18. In the evening, Robert E. Lee began withdrawing the remnants of his army from Maryland. George McClellan did not attack, despite having up to 24,000 fresh reserves. Lee’s withdrawal made the Battle of Antietam a tactical Federal victory, even though McClellan ignored pleas from President Abraham Lincoln to pursue and destroy Lee’s army. On the Atlantic Ocean, the Confederate commerce raider C.S.S. Alabama destroyed the whaler Elisha Dunbar off New Bedford, Massachusetts. Braxton Bragg announced that his Confederate troops had come to Kentucky to free the people from tyranny, not as conquerors or despoilers. Federal General James H. Carleton replaced General E.R.S. Canby as commander of the Department of New Mexico.
Friday, September 19. In Mississippi, Federals under General William Rosecrans defeated General Sterling Price’s Confederates at the Battle of Iuka. Rosecrans had arrived at Iuka as part of General Ulysses S. Grant’s advance guard, and the Confederates sought to prevent Grant from reinforcing General Don Carlos Buell in Kentucky. Price was awaiting the arrival of General Earl Van Dorn’s Confederates when the battle occurred. Rosecrans, knowing that Federal reinforcements were forthcoming, withdrew southward during the night. The Federal Department of the Missouri was reestablished, and the Department of Kansas was discontinued. In Maryland, George McClellan’s halfhearted pursuit of Robert E. Lee was halted by Confederate artillery.
Saturday, September 20. In Maryland, George McClellan’s Federals made one last effort at catching Robert E. Lee’s Confederates, but the Federals were repulsed at various points. In Washington, President Lincoln prepared the Preliminary Emancipation Proclamation, which he had first introduced to his cabinet in July.
Sunday, September 21. In Kentucky, Braxton Bragg’s Confederates advanced to Bardstown in preparation for linking with General Edmund Kirby Smith’s forces. However, this enabled Don Carlos Buell’s Federals to reach Louisville. In California, San Francisco residents raised $100,000 for aid to wounded and sick Federal troops.
Monday, September 22. In Washington, President Lincoln presented the Preliminary Emancipation Proclamation to his cabinet. Lincoln had been waiting for a military victory to issue the order, and Antietam provided the opportunity. The proclamation technically freed no one since it only applied to slaves in states that rebelled against the U.S.; it exempted rebellious states from freeing their slaves if those states rejoined the U.S. before January 1, and it exempted regions under Federal military occupation. Lincoln also called for congressional approval of compensated emancipation. Thus, the path was partially opened toward a constitutional amendment abolishing slavery.
Tuesday, September 23. In the Dakota Territory, Federals clashed with Indians at Fort Abercrombie. In Minnesota, Federals under H.H. Sibley defeated the Sioux Indians at the Battle of Wood Lake as part of the Dakota War. On the Ohio River, Confederate guerrillas plundered the steamer Emma at Foster’s Landing. In Tennessee, Federals retaliated against an attack on a ship by burning the town of Randolph. Word of the Preliminary Emancipation Proclamation was beginning to spread throughout the North.
Source: The Civil War Day-by-Day by E.B. Long and Barbara Long (New York, NY: Da Capo Press, 1971)