Paw Paw Tunnel

Paw Paw Tunnel
Paw Paw Tunnel - North Entrance

NPS / Nanette Nyce


Begun in 1836, the Paw Paw Tunnel (MM 156.1) project was initiated with optimism. Estimated to require a budget of $33,500 and take 2 years to construct, it ultimately became the last portion of the C&O Canal to be completed. The Potomac River makes several tight bends in this area, and the decision was made that a 3118 foot tunnel was preferable to 6 miles of canal following the path of the Potomac River, much of it lined by steep bedrock cliffs.

However, Sorrel Ridge is composed of unstable shale, siltstone, and sandstone, creased in folds that collapsed regularly as the workers attempted to dig through. There were also jealousies among the Irish, English, Welsh, and local ("Dutch" or Deutsch) workers from Maryland & Pennsylvania – each convinced that they deserved the work (and pay) more than the others. The lack of funds, in-fighting, and violent destruction of property by jealous and disgruntled workers halted construction in 1842. Finally, with a better appreciation for the resources and efforts required, the work resumed in November 1848 and was completed in October 1850, costing over $600,000.

Interior of Paw Paw Tunnel
Interior of Paw Paw Tunnel

Photograph by Randy Miller, courtesy of the C&O Canal Trust

Today, while occasional closures are necessary for maintenance, a trip through Paw Paw Tunnel is worth waiting for. Walking along the dark towpath Tunnel, deep in Sorrel Ridge creates a sense of scale as you contemplate the earth above. Make sure you bring a flashlight! Not only will it help you stay safe but observe many features commonly found in caves. Stalactites continue to form in the roof where water from the mountain above seeps through. With the Tunnel Hill Trail, you can also summit Sorrel Ridge, observing the winding path of the Potomac River and the ridges that cause its twisting shape. Because material was removed during construction by way of vertical shafts dug down to the Tunnel, piles of stone rubble (spoil heaps) can be found alongside your path in places as you walk the trail & towpath.

Paw Paw Tunnel Hill Trail
Sign showing directions toward Paw Paw Tunnel and Tunnel Hill Trail

Photo by Jim Rowan, courtesy of C&O Canal Trust

Discussion Questions: Geologists love dig sites, but they often pose unexpected challenges. Have you ever begun a project that became more difficult than you thought? What sacrifices might be necessary to accomplish innovative solutions? What makes successful teamwork possible?

Additional C&O Geology pages: Locks 15-20 | Widewater | Devils Eyebrow | Purplehorse Beach | Pothole Alley | Flooding | Lamprophyre Dikes | Mather Gorge | Olmsted Island | Cumberland Coal

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Last updated: September 6, 2023

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