Sideling Hill Creek Aqueduct at Mile 136.6 on the Chesapeake and Ohio Canal

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The Sideling Hill Creek Aqueduct is located at Mile 136.6 on the Chesapeake and Ohio Canal towpath. It cannot be accessed by vehicle, so reaching it requires hiking or biking .4 miles (one way) upstream from a parking area at Lock 56. See the Locks and Lockhouses web page for an interactive location map.

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A canal aqueduct is a nifty little feat of engineering that solves the problem of what to do when a canal crosses paths with a creek or river. Both are waterways, but the canal is a self-contained channel and cannot temporarily merge with the river because all of its water will spill out uncontrollably. The solution is to elevate the canal over the waterway via a bridge. In essence, a large, elevated bathtub must be built—water cannot be leaking out of the bottom and sides. This is done with a thick layer of clay and stone on the bottom and solid stone walls for sides.

Illustration of an aqueduct–the Catoctin Aqueduct–in use

The Sideling Hill Creek Aqueduct was built between the summer of 1837 and the spring of 1840. It is a 70-foot-long single-arch structure. Of the eleven aqueducts on the Chesapeake and Ohio Canal, six have a single arch for support.

Sideling Hill Creek Aqueduct (photo by Jerry Edmundson)

The aqueduct is no longer capable of holding water due to the loss of its berm-side parapet (retaining wall opposite the towpath). Unlike the Catoctin Creek and Conococheague Creek aqueducts that were restored by the National Park Service, it is doubtful that a structure this far from the tourist and population center of Washington, D. C., will ever be brought back to its former glory.

Missing berm-side parapet of the Sideling Hill Creek Aqueduct (photo by Jerry Edmundson)

Missing parapet of the Sideling Hill Creek Aqueduct at Chesapeake and Ohio Canal

Today, hikers and bikers are welcome to pass through the center of the aqueduct on the wide, dirt path, but when in service, this area would have been filled with water. The towpath is actually along the top of the parapet facing the Potomac River.

Towpath of the Sideling Hill Creek Aqueduct on the Chesapeake and Ohio Canal

The railroad bridge seen from the berm side of the Sideling Hill Creek Aqueduct was once a Western Maryland Railroad bridge. Twenty-eight miles of the old tracks have been turned into the Western Maryland Rail Trail. This is a paved trail that runs parallel to the Chesapeake and Ohio Canal’s towpath for much of its length. Hikers and bikers have the option to walk or ride on the dirt towpath or on the paved rail trail.

Western Maryland Rail Trail runs parallel to the Sideling Hill Creek Aqueduct on the Chesapeake and Ohio Canal

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