Lock 66 on the Chesapeake and Ohio Canal

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Lock 66 is located at Mile 154.7 on the Chesapeake and Ohio Canal towpath. It is not accessible by vehicle. The closest parking area is at the Paw Paw Tunnel Campground, and from there it is 1.5 miles downstream. See the Locks and Lockhouses web page for an interactive location map.

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Lock 66 on the Chesapeake and Ohio Canal is one of four locks located in the remote area of the Paw Paw Bends, and one of eight on a 15-mile stretch of the canal where there is no vehicle access (between the campground and the Fifteenmile Creek Aqueduct). Most of these locks are only seen by those hiking or biking part or the entirety of the C & O Canal.

Locks 66 through 60 are closest to the campground. It is a .6 mile walk from the parking lot along the towpath to the Paw Paw Tunnel. People are welcome to walk through the tunnel (bikers must push their bikes) to the downstream entrance, a distance of another .6 mile. From there it is a half mile to Lock 66.

There is some light in the Paw Paw Tunnel, but it is advised to bring a flashlight. I did not have one and made it without a problem, so it can be done. The original railing is still in place—believe it or not—so you can hold onto that. The only downside to walking in the near dark is that you may step into a water-filled pothole every now and then.

Upstream entrance to the Paw Paw Tunnel at Mile 155.8 on the Chesapeake and Ohio Canal towpath

Light at the end of the Paw Paw Tunnel on the Chesapeake and Ohio Canal

Once out of the tunnel, you will be walking through the Big Cut. This area of the canal is rocky terrain, so the canal bed had to be blasted out of the rocks, not simply dug into the dirt as is typically done when the canal follows closely to the river.

Big Cut section of the Chesapeake and Ohio Canal just downstream from the Paw Paw Tunnel

The rock in this area is composed of brittle Brallier Shale. Large slices often broke from the mountain slopes and crashed down upon the workers. Same thing can happen today but to hikers and bikers. Braces have been installed into the rock to help prevent the shearing, but stopping it completely is not possible. Every so often, the National Park Service removes loose sections of rock and installs new braces.

Braces installed into the shale along the Big Cut section of the Chesapeake and Ohio Canal near the Paw Paw Tunnel

Lock 66 is one of thirteen locks at the upper end of the Chesapeake and Ohio Canal that was made from a composite of wood and uncut stone. The reason is because this end of the canal was constructed in the 1840s (opened in 1850), and by this time it was evident that the railroad was going to put it out of business. To save money, the walls were made of uncut stones with large gaps between them, which was not going to hold water. A wood lining was attached to help solve the leakage problem. In most cases the wood didn’t work that well, and starting in 1891, much of it was replaced with concrete. That does not appear to be the case at Lock 66 since the uncut stones still remain visible. None of the wood exists today, but you can still see the bolts at the top of the stone walls that held it in place.

Bolts in the wall of Lock 66 on the Chesapeake and Ohio Canal were used to anchor a wood lining to the stone

While no wood remains on the walls, there is some along the bottom of the lock, with a good bit remaining at the upstream end. I am not aware of wood being used to line the bottom of a composite lock, but perhaps it was. It is amazing that the wood on the walls has disappeared, yet wood soaking in water for 175-plus years is still around. The wood was “kyanized,” meaning it was treated with mercuric chloride to prevent decay. This seems to have worked very well.

Wood at the bottom of Lock 66 on the Chesapeake and Ohio Canal

There is a stone structure with some sort of barrel still in place. I am not sure what this is, but there was a carpenter’s shop at Lock 66 that burned down in the 1960s. Perhaps this structure and barrel are part of the former shop.

Remains of a carpenters shop at Lock 66 on the Chesapeake and Ohio Canal

If you continue downstream to the next lock, which is just a tenth of a mile away, you will not find Lock 65. You will find Lock 64 2/3. The anomaly in the numbering system stems from the construction of the locks downstream from the Paw Paw Tunnel. Engineers originally planned to build four but needed only three. Since the locks had already been numbered, instead of redoing the entire system, they just skipped over the name Lock 65.

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