Reinforced by the troops he had left in Richmond, Lee headed north, crossing the Potomac.  He was soon forced to confront a problem that would play a major role in the campaign.  Thousands of tired soldiers had fallen behind their regiment, and were trailing the army.  To prevent their certain capture if they crossed the river they were directed west to Winchester.  Lee was going to face the enemy without full force, because so many just dropped out of the ranks, cause they did not to attack northern homes.
 

   With Lee north of the Potomac Lincoln was in trouble.  Lincoln had no other choice but to pick George McClellan as general.  McClellan left with two beat-up corps in Washington, he set off after Lee.  He had about 80,000 soldiers under his command.
 

    By this time Lee was in Frederick where he issued Special Orders 191 to his commanders.  They directed Jackson to take his three divisions west, and cross the Potomac.  As McClellan entered Frederick on the same day, in a stroke of luck some of his men found a copy of Special Orders 191.  He now knew how he could relieve Harpers Ferry and defeat Lee’s army piece by piece.  The next day he would attack Lee at South Mountain

    Lee decided to make his stand outside of Sharpsburg, Maryland.  With the Potomac only a mile to his rear.  Lee’s army was small only about 26,000 men against 70,000 men of the Union Army of the Potomac.  Lee would half to wait for the remainder of Jackson’s army to come if he wanted to make a stand.  Lee was unable to prevent McClellan from crossing Antietam Creek.  So Lee settled on a defensive posture along the ridge lines to the north and east of town.  Jackson’s Corps occupied the ground north of town.  Hooker’s 1 Corps crossed Antietam Creek via the Upper Bridge.  Longstreet’s Corps stretched from northeast of town and southeast along Antietam Creek.
 

The battle started at 6a.m. when General Meade of Hookers Corps marched his division southward from the North Woods towards Dunker Church and the Confederate troops of Lauton.  During the battle Hooker was wounded and taken from the battle field.