Located at Mile 106.5, Dam 5 is one of 2 "high rock" dams along the canal. It's about 700 feet long and 20 feet high. The original dam was made of timber and didn't last long but the current masonry dam has been here since 1860. That's the Potomac Edison power plant on the other side built in 1918 and still working.
We encounter another story of Gen. Stonewall Jackson here. The Confederates tried and tried to blow this dam up and even tried to dig under its foundation to breech it and thereby rid it useless to the Union forces. They pretty much failed in their efforts.