File:Lock 75 C and O Canal From NPS.jpg

English: Lock 75, last lift lock on C and O Canal. NPS site says; This is a standard cut stone lift lock of gray limestone with a bypass flume on the berm side. The lock was built to 1836 specifications and is typical to that standard. It is 700' above Lock 74 and is the last of the numbered lift locks on the canal. There are equally space bolts protruding above the coping that indicate that a continuous 6" wood coping had been added to deepen the canal, but no timber remains. The 4' long upper extension wall is grooved vertically midway up to receive drop planks. This lock was fitted with a drop gate atop the breast walls to replace the upper gates, but nothing remains of the gate or its operating mechanism. The upper wingwalls flare out about 60 degrees above the upper extension wall and run for about 13'. The towpath buts into the upper towpath canal wall and the berm, then returns on itself to run for 6’ parallel to the lock. This wall becomes the lock side of the bypass flume entrance. The lower extension walls run for 13' and flares out at about a 60 degree angle. The lower towpath wingwall runs for about 14½' to butt into the 100' long dry laid stone wall of the lower canal and towpath rise. The berm wing runs for 143', turns again to run perpendicular to the lock for 8'4" before butting into the 6' deep, 8' wide notch for the by-pass flume exit. After the exit, the wall returns to full height to run another 8½' into the lower canal berm bank. This last portion of wall is buttressed by a 3' thick, stepped wall, which extends down canal for 50'. A pair of good condition, creosoted, lock gates remain in a closed position in the lower lock gate pocket. The gates have lost their balance arms. The walls’ minimum clear width is 14'-5" just below the upper gate pockets.