Since this is September, I thought I would mention an important Confederate victory that took place September 12-15, 1862, the Battle of Harpers Ferry, which took place in and around the town of Harpers Ferry, Maryland. This battle was part of the Maryland Campaign of the War Between the States.
Confederate General Robert E. Lee was in Maryland, being pursued by Maj. Gen. George B. McClellan’s Northern Army of the Potomac, outnumbering Lee two to one. Lee chose the risky strategy of dividing his army, sending one portion to attack Harpers Ferry under the command of General Thomas “Stonewall” Jackson.
Union commander, Col. Dixon S. Miles insisted on keeping most of his troops near the town of Harpers Ferry, rather than on the surrounding heights, so he played right into Jackson’s hand, enabling the Confederate General to attack from three directions and overwhelm the Yankees. When Union Col. Miles realized the situation was hopeless he raised the white flag of surrender, but before Miles could surrender personally, he was mortally wounded.
 
The National Park Services says the Union army surrendered 12,700 men that day, the largest surrender of Federal forces in the war.
 
Wikipedia quotes Stephen Sears in his book, “Landscape Turned Red: The Battle of Antietam. Sears writes as follows:  “Jackson sent off a courier to Lee with the news. ‘Through God’s blessing, Harpers Ferry and its garrison are to be surrendered.’ As he rode into town…Union soldiers lined the roadside, eager for a look at the famous Stonewall. One of them observed Jackson’s dirty, seedy uniform and remarked, ‘Boys, he isn’t much for looks, but if we’d had him we wouldn’t have been caught in this trap.’ By early afternoon, Jackson received an urgent message from General Lee:
‘Get your troops to Sharpsburg as quickly as possible.’ Jackson left A.P. Hill at Harpers Ferry to manage the parole of Federal prisoners and began marching to join the Battle of Antietam.”