General Custer's brigade reorganized and advanced toward the summit. For the next several hours in the rain and darkness, the opposing forces engaged in some of the most confusing and chaotic fighting of the Civil War. In some instances, the soldiers could only tell where the enemy was by flashes of the muzzle from their guns, the cannon or lightning in the sky that illuminated their positions.
Gaining the eastern side of the summit, Kilpatrick ordered the 1st Vermont Cavalry to Leitersburg in order to attack the Confederate wagons as they came off of South Mountain. He also ordered a portion of the 1st Michigan Cavalry to attack Fairfield Pass, one mile east of Monterey Pass.
Near the Monterey House, General Kilpatrick deployed a section of artillery and shelled the Confederate battle lines that were positioned near the modern day Lion’s Club Park. By 3:00 am, along a creek just west of the Monterey House, Custer's men, supported by artillery, dismounted and attacked Captain Emack who was near the Tollgate house. Fighting raged in the woods near the modern day intersection of Route 16 and Charmain Road, leaving Captain Emack wounded by shell, shot, and a saber. As the battle of Fairfield Gap came to a close, Captain Emack was finally reinforced by other companies of the 1st Maryland Cavalry as well as the 4th North Carolina Cavalry, as Custer's men approached. During the thickest of the fight, General Jones ordered his couriers and staff officers to get into the fight as well as the wounded that could fire a gun.
The 5th and the 6th Michigan Cavalry were ordered to dismount, leaving the 7th Michigan and two companies of the 5th Michigan in reserve. While Custer was rallying his men, a bullet struck his horse. It was at this time that the 1st West Virginia Cavalry and a portion of the 1st Ohio were ordered to the front to support Custer’s bogged down battle line. The West Virginians charged the Confederate cannon, tumbling it down the embankment and began destroying wagons and taking on prisoners.
The Sharpshooters of the 1st North Carolina Battalion and the 6th Virginia Cavalry arrived in time to halt the wagons approaching from Fairfield Gap. Two guns from Pennington's Battery poured case shot into their ranks from their position near the Monterey Toll House. During the fight, the 6th Virginia Cavalry retreated back toward Fairfield, refusing to come up until after daybreak. The sharpshooters might have saved the rear of the wagon train, but the wagons that were traveling toward Waterloo were in grave danger.
As soon as the West Virginians cleared the pass and began its charge down the mountainside, Custer and his troopers finally began storming through the long line of wagons, “like a pack of wild Indians” overturning many wagons and setting fire to others as the Union cavalry collected their bounty until dawn. In some instances, panic stricken horses with no where to go fell off the mountain cliffs and overturned into the steep ravines. At the bottom of the mountain sat several hundred wagons guarded by the 36th Virginia Cavalry. In the wake of the Union charge, the 36th Virginia had no chance and withdrew from the battlefield.
While the wagons at Waterloo were under attack, back at Monterey Pass, just before daybreak, Chew's Battery, the 6th Virginia Cavalry as well as General Iverson's North Carolina Brigade arrived. General Wright's Brigade was a few hours behind, forcing Kilpatrick to give up the fight at the actual mountain pass. Realizing that his cavalry was divided at Leitersburg and Waterloo, Kilpatrick withdraws from Monterey Pass fighting remains of Confederate cavalry units down the mountain.
The fight then continued into Maryland, making this battle the only one fought on both sides of the Mason and Dixon Line. Once Kilpatrick was at Ringgold, Maryland he ordered his cavalry to halt. The wagons that were not destroyed were burned in the open fields at Ringgold. A portion of the 1st Vermont Cavalry met Kilpatrick at Ringgold after the destruction they caused at Leitersburg.