During Robert E Lee’s Maryland campaign of 1862 it was decided and laid out in the infamous General Order 191 that Harpers Ferry needed to be “taken out”, to use a modern term. It was on Lee’s line of communications and the yankees were not cooperating by not evacuating. So, when all was said and done and the plan was carried out, Harpers Ferry was surrounded by infantry and artillery on the 3 heights surrounding it. A Federal soldier had written that if these three heights could not be held, Harpers Ferry would be “no more defensible than a well bottom.” The troops under Colonel Dixon Miles were in a fix.
Alabama born and Mississippi bred, Col. Benjamin F. “Grimes” Davis proposed to Miles that his troopers of the 12th Illinois Cavalry, the Loudoun Rangers, and some smaller units from Maryland and Rhode Island, attempt to break out. Cavalry forces were essentially useless in the defense of the town. And with mobility they had a better chance to fight another day. Miles dismissed the idea as “wild and impractical,” but Davis was adamant and Miles relented when he saw that the fiery Mississippian intended to break out, with or without permission. Davis and Col. Amos Voss led their 1,400 cavalrymen out of Harpers Ferry on a pontoon bridge across the Potomac, turning left onto a narrow road that wound to the west around the base of Maryland Heights in the north toward Sharpsburg. Despite a number of close calls with returning Confederates from South Mountain, the cavalry column encountered a wagon train approaching from Hagerstown with James Longstreet’s reserve supply of ammunition. They were able to trick the wagoneers into following them in another direction. Davis’ orders to the wagoneers in his Missisippi accent doing the trick. And they repulsed the Confederate cavalry escort in the rear of the column. Capturing more than 40 enemy ordnance wagons, Davis had lost not a single man in combat, the first great cavalry exploit of the war for the Army of the Potomac.
Grimes Davis died while rallying his regiment at the Battle of Brandy Station on June 9, 1863, a prelude to the Battle of Gettysburg and the biggest cavalry battle of the war. He is buried at West Point surrounded by such notables as John Buford, George Armstrong Custer, Judson Kilpatrick, Thomas C. Devin, and Alonzo Cushing.