Upstream entrance to the Paw Paw Tunnel in Chesapeake and Ohio Canal National Historical Park

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NOTE: Sections of the towpath, locks and other historical structures, trails, campgrounds, picnic areas, boat ramps, and visitor centers are constantly being closed due to damage and/or repair. When planning an adventure within Chesapeake and Ohio Canal National Historical Park, make sure that areas you plan to visit are open by checking the National Park Service’s official Current Park Conditions web page.

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Length: 3.5-mile loop
Time: 2 hours
Difficulty: Moderately strenuous

The Paw Paw Tunnel is located in a mountainous area of the Potomac River Valley known as the Paw Paw Bends. Over the course of six miles, the river zigzags three times and is flanked by rock cliffs. Cutting a canal into the rock along the river would have been next to impossible, so canal engineers had two choices. One, they could dam the Potomac at the downstream end of the Bends so that the river could be made deeper and thus navigable at all times. Boats would leave the canal and travel directly on the river.

A second option was to create a nearly six-mile shortcut around the Bends by cutting through the interior. The only problem was that there was a mountain in the way. With an estimated cost of $33,000 and a completion date of two years, it was decided to tunnel through the mountain, a decision that nearly bankrupted the C&O Canal Company. Work began in 1836, and when the tunnel opened in 1850, twelve years behind schedule, it had cost $600,000.

Illustration of the canal route using the Paw Paw Tunnel (click to enlarge)

The Paw Paw Tunnel Hill Trail (aka Tunnel Bypass Trail) in Chesapeake and Ohio Canal National Historical Park takes hikers up and over the mountain that the Paw Paw Tunnel was cut through. It starts near the tunnel’s upstream entrance and comes out on the other side of the mountain on the C&O Canal towpath just a short ways from the tunnel’s downstream entrance. There’s no sense hiking back to the starting point by going over the mountain a second time, so make a loop out of the hike and return through the tunnel. It is advised to bring a flashlight, not only so you can make it safely in the dark, but also so you can see the interior features. However, I did not have one and made it through without a problem, so it can be done. There is a railing you can hold onto. The only downside is that you may step into a water-filled pot hole every now and then.

The tunnel and trailhead themselves are located a half mile down from the Paw Paw Tunnel parking area—which is at the Paw Paw Tunnel Campground—at the end of a gravel road. This was the towpath when the C&O Canal was in operation; the canal is on your left.

Gravel path from the Paw Paw Tunnel parking area to the start of the Paw Paw Tunnel Hill Trail in Chesapeake and Ohio Canal National Historical Park

You can start the hike either through the tunnel or by going over the mountain. I chose to tackle the mountain first. When at the tunnel, the trailhead is to the right of the entrance.

Start of the Paw Paw Tunnel Hill Trail in Chesapeake and Ohio Canal National Historical Park

While described as strenuous by the National Park Service, the trail is certainly difficult, but because the path up the mountain is often composed of switchbacks, it could be worse. Switchbacks, which are S-shaped curves, allow hikers to scale the mountain gradually, so while the route is longer than heading straight up, the climb is much easier.

Typical terrain up the mountain on the Paw Paw Tunnel Hill Trail in Chesapeake and Ohio Canal National Historical Park

It is approximately a half mile to the top of the mountain. Great views of the Potomac River valley await those who make the climb.

View of the Potomac River valley from the apex of the Paw Paw Tunnel Hill Trail in Chesapeake and Ohio Canal National Historical Park

The descent from the top is much more gradual than the hike up, but it is much longer. There are no switchbacks, so it is one continuous downhill stretch. Also, the trail is an old service road, not a traditional earthen hiking trail like on the way up. The road was built for the tunnel workers. Two vertical shafts were sunk into the mountain and connected to the tunnel. Debris could be hauled up and out through the shafts instead of having to cart it all the way back to the tunnel entrance. Once out of the tunnel, the debris was transported down this road for disposal.

Typical terrain on the Paw Paw Tunnel Hill Trail as it descends from the top of the mountain

Illustration of the vertical shafts that connect to the Paw Paw Tunnel

As mentioned earlier, the Paw Paw Tunnel Hill Trail does not come out on the other side of the mountain at the tunnel entrance like it does at the start. Instead, it meanders down the mountain and reaches the towpath about .4 mile from the tunnel. The National Park Service states that the trail’s distance is 2 miles, but that is from the trailhead at the upstream tunnel entrance to this point and does not take into consideration the walk back, either over the mountain or through the tunnel. In fact, it doesn’t even take into account the mile round-trip walk from the parking lot.

Of course you’d have to be insane to hike back over the mountain, so when you reach the towpath take a left to return via the tunnel. You are now walking through what is known as the Big Cut. The shortcut around the Paw Paw Bends is over 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.

The Big Cut section of the Chesapeake and Ohio Canal near 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

View of a brace where the shale still managed to shear away from the cliff along the Big Cut section of the Chesapeake and Ohio Canal near the Paw Paw Tunnel

Hunk of shale that fell onto the Chesapeake and Ohio Canal towpath near the Paw Paw Tunnel

Going through the Paw Paw Tunnel in the dark is an interesting experience. First off, you can see the light at the end of the tunnel for most of the way, despite the fact that it is 3,118 feet long (.6 mile). This gives the illusion that the end is just up ahead, yet the light never seems to get any bigger or any closer. If you do not have a flashlight, just hold on to the railing (the original railing from the canal days). If you have ever been walking down steps and thought you were on the last step only to find yourself surprised by one more, well there are a lot of those moments as you step into holes filled with water. There are also spots where the ground is raised, so your step comes to an end sooner than expected. That is, however, the extent of the danger.

Downstream entrance to the Paw Paw Tunnel on the Chesapeake and Ohio Canal

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

Exiting the Paw Paw Tunnel on the Chesapeake and Ohio Canal

The hike is 3.5 miles from start to finish, an extra 1.5 miles beyond the National Park Service’s stated distance for the Paw Paw Tunnel Hill Trail. The hike is well worth the effort because you get some nice views and pass a few historical areas. When hiking in a history-based park—versus a park known for its beauty—I want the trails to add something to the historical aspect of my visit. Walking through the Paw Paw Tunnel and across the mountain that it was cut through certainly expands the C&O Canal experience.

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