The Confederate army under Robert E Lee continued to threaten Washington in September 1862. However, September saw Lee face a set-back at Sharpsburg and at the Battle of Antietam, which Lincoln declared a victory for the North.
September 1st: The Second Battle of Bull Run ended when sections from both sides clashed at Ox Hill. They came across one another just before nightfall during a thunderstorm. In the clash Union Generals Isaac Stevens and Philip Kearney were killed.
September 2nd: General McClellan was recalled to Washington DC by President Lincoln to take charge of the capital’s defences. “If he can’t fight himself, he excels in making others ready to fight." (Lincoln)
September 5th: Robert E Lee took his army into Maryland. At the same time the Union’s military hierarchy could not make its mind up as to who should lead the Union’s army in the field. Maryland was a tempting target for Lee as its fields were full of crops and any move north that he made would bring fear to those who lived in the capital who would have rightly believed that the city was his priority target.
September 8th: The cause of the Union was not helped by dissension in the most senior ranks of the Union Army. General Pope openly blamed other generals for the failure at Bull Run, while they (Generals Franklin and Porter) cited his incompetent leadership during the battle. Leaving this dispute behind in the capital, McClellan marched his men out to meet Lee away from the city. His army of 90,000 was twice as large as Lee’s Army of Virginia but the men in it were very demoralised after the Second Bull Run while Lee’s men were full of confidence.
September 9th: The people of Maryland did not greet Lee’s army with any enthusiasm despite his proclamation that his intention was to return the state to the Confederacy – which Lee assumed would sell his cause. The expected provisions were not forthcoming and Lee’s army remained short of supplies.
September 10th: McClellan marched his men to where he knew Lee’s army had encamped – Frederick. However, Lee’s army marched off on the same day as McClellan gave his order. Lee split his men in two with Jackson ordered to capture Harper’s Ferry while he would lead his men to Hagerstown.
September 13th: In an astonishing twist, two Union soldiers found some cigars where Lee had made his camp. They were wrapped in paper. On this paper was written Lee’s next plans for his army – their targets, which part of his army was marching where etc. This was Lee’s Special Order 191. The Confederates knew that they had lost one copy but must have assumed that it was never going to be found by the North.
September 14th: The North, with the knowledge of where Lee was and where he was heading, made a series of attacks on the Confederates at South Mountain. The speed of McClellan’s chase unnerved Lee and forced him into changing his plans at the last minute. The problem Lee would face was to ensure that his change of plans got out to his commanders in the field and that they all understood them.
September 15th: Harper’s Ferry fell to Jackson who captured 12,000 Union troops. Jackson left behind an occupying force and then marched at speed to rejoin Lee to consolidate the Army of Virginia once again.
September 16th: Lee’s army was at Sharpsburg – as was McClellan’s. Lee faced two serious problems. First, he only had 18,000 men with him against 75,000 Union troops. Second, behind where his men were gathered was the Potomac River. So if Lee needed to withdraw, he would have to cross the river. McClellan started his attack with an artillery bombardment. Lee was reinforced when Jackson’s 9,000 men arrived. No decisive impact was made one way or the other on this day.
September 18th: The two armies continued to face one another at Antietam Creek. Two fresh Union divisions arrived but they were ordered to “rest" by McClellan. Lee started to make plans to withdraw his men.
September 19th: In the early hours of the 19th, Lee withdrew his men across the Potomac River. Though McClellan believed Lee would strike across the river again, he was wrong. Lee had ordered his men to the relative safety of Winchester in the Shenandoah Valley.
September 20th: McClellan kept his men at Sharpsburg and showed no inclination to pursue Lee’s men. However, any thoughts Lee had of taking Maryland were killed off in what McClellan called “a very great battle".
September 22nd: Lincoln expressed his belief that the Battle of Antietam was a victory for the North in the sense that it stopped any plans Lee had for capturing Washington DC. In the same speech, Lincoln declared his intention of abolishing slavery throughout the United States and that this was now a major aim of the Union’s war effort.
September 24th: Lincoln suspended habeas corpus for those who tried to evade the militia draft.
September 28th: Lee’s army of 50,000 men gathered at Winchester in the Shenandoah Valley.