Likely the most important Federal arsenal in Virginia, Harpers Ferry was a point of conflict between the Union and confederacy almost as soon as Virginia seceded from the Union. This was important because Harpers Ferry, being an arsenal, had a large quantity of weapons and ammunition. These supplies would, of course, be invaluable to any army who controlled the arsenal. This is why General Jackson of the Army of Northern Virginia was ordered to take the arsenal.
The attack began on the 12th of September, 1862. The hills above the arsenal, Maryland Heights, held a commanding view of the Harpers Ferry for heavy guns. There was skirmishing on the heights that day. The problem with the Union defense of Harpers Ferry was that Colonel Miles concentrated on the town and arsenal of Harpers Ferry, leaving only about 1600 men and a few cannon on the heights to defend them. These troops, many being green recruits from New York, fought well on the 12th and, on the 13th, held the heights until their remaining commanding officer was wounded, the other having been too ill to take the field. The Confederate troops flanked the Federal line, and the troops retreated at the word of Colonel Ford, the officer who was sick.