September 12th, 1862, the Battle of Harpers Ferry, which was part of the Maryland campaign, began. General Robert Edward Lee divided his army and had Stonewall Jackson lead a division to Harpers Ferry as he led the rest of the Confederates to Hagerstown, Maryland. Stonewall positioned artillery on the hills next to the town leaving the Union forces at a severe disadvantage.
The battle resulted in the Union soldiers burning down the federal armory since they were outnumbered and outgunned by Confederate forces. The battle ended with the Confederates taking on over 12,000 Union prisoners on September 13th.