During Confederate Gen. Robert E. Lee's first invasion of the north, Gen. Thomas J. "Stonewall" Jackson's capture of the Union garrison at Harper's Ferry resulted in the largest surrender of United States troops before World War II.
In September 1862, when Robert E. Lee and the Army of Northern Virginia crossed the Potomac River into Maryland during Lee’s first invasion of the north, it was expected that the Union forces garrisoned at Harper’s Ferry would be forced to retreat. Surprisingly, they did not. Harper’s Ferry was crucial to Lee’s invasion because it meant an open line of communications and supplies through the Shenandoah Valley. To ensure the success of his invasion, Harper’s Ferry had to be taken.

On September 13th, under the command of Gen. Thomas “Stonewall” Jackson, Confederate forces approached Harper’s Ferry from three sides, taking control of the heights surrounding the town. With the heights in his control, Jackson deployed his artillery and tried to ensure there was no route of escape for the Union troops.
On the evening of September 14th however, Union cavalry under Col. Benjamin F. Davis made a desperate break out attempt. Under the cover of darkness, and with some luck, the 1,500 men were able to cross Potomac River undetected. The cavalry troops not only escaped, but would also capture 91 Confederate ammunition supply wagons. Although the escape was successful, over 12,000 men were still trapped in Harper’s Ferry.

On the morning of September 15th, after a council of war with his commanders, Union commander Col. Dixon S. Miles agreed that surrender was their only option. (Dixon was mortally wounded by a shell before the surrender took place.) With the surrender, Jackson would capture 12,000 soldiers, 13,000 arms, and 47 pieces of artillery. The surrender at Harper’s Ferry would be the largest surrender of United States soldiers until Bataan in 1942.
“All seem to think that we will have to surrender or be cut to pieces.” – Union Pvt. Louis B. Hull, 60th Ohio
With Harper’s Ferry secured, Jackson’s men would begin the march to rejoin Lee in Maryland. Arriving near Sharpsburg, these soldiers would arrive just in time to bolster Lee’s army and help save him from disaster in the Battle of Antietam, the bloodiest single day in American history.