Lock 68 - Crabtree's Lock
Mile 164.8 - This lock is located at the geographically important point at which the Potomac River forks into a North and South branch and is the site of the proposed Dam 7 which was never built. Because the Potomac River is the boundary between Md. and Va., there was a boundary dispute between these two states until the North Branch was declared the continuation of the Potomac. The South Branch could have been used to water the canal which is why the initial plans for the canal included a dam.
This nearby bridge was a road from the old Md. Route 51 to a ferry across the South Branch.