"Before night our town changed hands five times!"
— Antietam Campaign 1862 —
On the evening of September 5, 1862, Gen. Wade Hampton's and Gen. Fitzhugh Lee's Confederate cavalry brigades bivouacked around Barnesville. They rode the next day to their base camp at Urbana, leaving the 9th Virginia Cavalry to guard Barnesville.
The next few days were peaceful here, but on September 9 the war came to Barnesville in a hurry, past this very spot. The 8th Illinois Cavalry, following a skirmish with the 12th Virginia Cavalry at Monocacy Church, pushed on to Barnesville and struck part of the 9th Virginia Cavalry just south of town in the afternoon. The outnumbered Virginians raced by here through town, and two miles north they found the rest of their regiment as well as the 7th Virginia Cavalry. Suddenly it was the Federals' turn to be outnumbered; the fled south down Beallsville Road, with the Confederates on their heels. South of town, two companies and a battery of the 3rd Indiana Cavalry reinforced the hard-riding Union cavalrymen, and everyone wheeled around and galloped up this road as the Federals chased the Confederates toward Sugarloaf Mountain. Believing that they had at last cleared the town of their opponents, Union cavalry returned and rode past here south of Barnesville. That evening, however, the Confederates briefly occupied the town again but retired the next morning to Sugarloaf Mountain, which stands directly in front of you. The Confederates lost one cavalryman dead, five wounded, and 19 captured, while the Federals lost none. The number of horses lost to exhaustion are unknown.
The next day, Union infantry arrived at Barnesville in the evening. Gen. William B. Franklin's VI Corps of the Army of the Potomac camped just south of town.
Like Poolesville, Barnesville was a hotbed of Southern sympathizers. At least five local residents are known to have "gone South" (joined the Confederate forces). Prominent citizen Leonard Hays, whose son served in the 35th Virginia Cavalry, hosted J.E.B. Stuart's brigade commanders, Col. Thomas Munford, Gen. Wade Hampton, and Gen. Fitzhugh Lee, for dinner on September 5.