The following day the Confederates prepared to cross the Potomac and head into West Virginia but found the bridges over the Chesapeake and Ohio Canal had been burned by Col. Israel Stough and his regiment of 100-days troops. Stough deployed his force on the spit of land between the canal and river to contest the Confederate advance towards the river. After repulsing a charge by the enemy cavalry, Stough was forced to retreat across the Potomac when the 21st Virginia successfully constructed a bridge and crossed the canal on his left flank. On the south bank of the river the Federals took cover in a blockhouse on the B&O Railroad and an armored ordnance train operated by the Potomac Home Brigade that was stopped on the line. In the face of rifle and artillery fire, John R. McNulty's artillery was brought across the canal and his best gunner employed to take out the train. After firing two well placed shots, one which hit the train's boiler and one that knocked out the train's gun, the Federals abandoned the train, most fleeing into the woods in terror. Those in the blockhouse remained to contest the Confederate crossing. McCausland briefly considered an all out charge on the blockhouse, but then thought it wise to first demand its surrender. The Federals in the blockhouse agreed to the terms of surrender, and the Confederates crossed the river and headed to Springfield, West Virginia, where they rested until the 4th.
Although the action around Cumberland was tactically inconclusive, Kelley's stand saved the town from likely being burned and greater damage being inflicted on the railroads. The stubborn resistance of Stough at the Potomac represented the first time McCausland's force had been contested since burning Chambersburg.