Monocacy Aqueduct on the Chesapeake and Ohio Canal

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The Monocacy Aqueduct is located at Mile 42.2 on the C&O Canal towpath. There is vehicle parking at the site. See the Locks and Lockhouses web page for an interactive location map.

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The Monocacy Aqueduct is a 560-foot, seven arch aqueduct that spans the Monocacy River. Except for dams, it is the largest structure on the Chesapeake and Ohio Canal.

East side of the Monocacy Aqueduct on the Chesapeake and Ohio Canal

West side of the Monocacy Aqueduct on the Chesapeake and Ohio Canal

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

Of course mules had to be able to tow the canal boats through the aqueduct, so one of the walls was built wide enough to accommodate them. Today, hikers have the option of staying on the towpath or walking down the middle of the waterway. Bikers will find the waterway the easiest way across.

Towpath of the Monocacy Aqueduct on the Chesapeake and Ohio Canal

Waterway of the Monocacy Aqueduct on the Chesapeake and Ohio Canal

The ruins of an old warehouse are also on the property. This is all that remains of a number of buildings that stood during the heyday of the Chesapeake and Ohio Canal.

Warehouse at the Monocacy Aqueduct on the Chesapeake and Ohio Canal

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