While the mill was still under Folck family ownership in 1864, General Benjamin F. Kelley led Union soldiers against Confederates marching towards Cumberland, MD. The Confederate troops had orders to destroy parts of the B&O Railroad and cut off major supply and transportation lines for the Union troops. Before arriving at this site, the Confederate troops led by Brigadier General John McCausland had set fire to the town of, Chambersburg, PA. The troops met near the mill and became known as the Battle of Folck's Mill or the Battle of Cumberland. There were 38 total casualties from the battle. Though neither side is credited with victory, the Confederate troops were turned away from Cumberland and retreated to the Potomac River as a result of the battle. This often leads to the battle being discussed as a Union victory. The stones show signs of damage from shots fired during the battle. There is also some evidence that the mill may have caught fire during the battle.
Today, the site of the mill is owned by the Maryland State Highway Administration and is located just off of I-68. Folck's Mill was added to the National Register of Historic Places for its significance as a Civil War battleground in 2009.