Lock and Lockhouse 46 at Mile 107.2 on the Chesapeake and Ohio Canal towpath

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Lock and Lockhouse 46 are located near Clear Spring, Maryland, at Mile 107.2 on the C&O Canal towpath. There is parking at the site. See the Locks and Lockhouses web page for an interactive location map.

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Lock 46 on the Chesapeake and Ohio Canal is located 300 yards upstream from Lock 45. Just .6 mile farther downstream is Dam 5. Between the dam and Lock 45, canal boats traveled directly on the Potomac River, saving the C&O Canal Company the expense of digging a canal. For this to happen, the river must be deep enough to be navigable year-round, which was achieved by Dam 5 backing up the Potomac to create what was essentially a long, narrow lake.

While it would appear to be a money saving decision, there was a technical reason for the canal bypass as well. Between Lock 45 and Dam 5 is a cliff, and it would have been impossible to blast a canal into the rocks. In fact, the towpath between the two is a concrete path that hugs the rock walls.

Concrete towpath cut into the cliffs along the Potomac River between Lock 45 and Dam 5 on the Chesapeake and Ohio Canal

So what does the fact that canal boats entered and exited the canal at Lock 45 have to do with a discussion of Lock 46? Well, though boats used the Potomac River, they were still pulled by mules. The mules had to be able to switch from the berm side of the canal (opposite of the river) where the towpath was located upstream of Lock 46 to the river side so they could pull the boats along the Potomac. When you are at Lock 46 and looking downstream, notice the retaining wall on the river side and the arched structure on the berm side. These were abutments for a bridge the mules used to get from one side of the canal to the other.

Downstream view of Lock 46 on the Chesapeake and Ohio Canal

The arch was also part of the Lock 46 sluice, which ran underneath the bridge. All locks had them, but today many have been filled in with dirt or are covered in vegetation and hard to spot. In most cases, the sluice was just a rudimentary ditch that ran parallel to the lock. When the upstream gates were closed, the sluice allowed water to flow around the lock instead of backing up into a pool of excess water that could spill over the banks of the canal or put additional pressure on the lock gates. The water emptied back into the canal just past the downstream gates. The idea is similar to that of a spillway on a dam. Here at Lock 46, while the culvert of the sluice exists, the channel itself has been filled in with dirt. You can, however, see the slight depression of the former ditch.

The arched culvert was part of the sluice for the Chesapeake and Ohio Canal’s Lock 46

Along with the lock itself stands Lockhouse 46 (not open to the public). A lockhouse is the residence of the man who is hired to operate the lock. In addition to a yearly salary, he and his family—almost all lockkeepers were family men—lived in the company provided lockhouse and had use of an acre of land for farming. Those who tended multiple locks got extra money per lock, up to two. The lockkeeper for Lock 46 also operated Lock 45.

Operating the lock was a year-round, 24-hour-a-day job. When a canal boat approached, the captain would blow a whistle to notify the lockkeeper. If it were nighttime, somebody had to wake up and go to work. Of course that’s the benefit of being a family man—your kids had to get up for the late night and early morning arrivals!

Lockhouse 46 on the Chesapeake and Ohio Canal

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