Dam No. 4 is nearly 800 ft across and stands 20 ft high. An original structure composed of "rock rubble" with timber cribs, Dam No. 4 was rebuilt as a masonry "high rock" dam after incurring severe flood damage. At this stop gate the winch house has been restored. Historically, the winch house was used to raise and lower the gate beams permitting canal boats to pass.
Photo Credit: C&O Canal National Historical Park