Heading upstream from Georgetown, the Monocacy River Aqueduct is the second of eleven such structures on the C&O Canal. It’s located just upstream from mile marker 42, and at 560′ feet in length, it is easily the longest of the aqueducts. It contains seven arches, each spanning 54′, and a look from the top (heading downstream) offers a wonderful view of the Potomac River–which by this stage of its course is a large and powerful stream.
The Monocacy River is the Potomac’s largest tributary on the Maryland side between Cumberland and Georgetown. With this in mind, flooding and debris are problems that have plagued the aqueduct over the years. The seven supports catch much of the floating debris as it heads downstream, and this puts a tremendous strain on the structure. At one time, the aqueduct was fronted with steel supports, much like those seen on the Sideling Hill Creek and Tonoloway Creek aqueducts.
At one time, the Monocacy River Aqueduct was considered to be one of America’s eleven most endangered historical structures, and in 1998 then First Lady Hillary Rodham Clinton was among the advocates who spoke out in favor of its preservation. With the wheels set in motion, the aqueduct’s restoration was completed in 2005, and it now stands as perhaps the most impressive structure on the C&O Canal. For those interested, Robert and Elizabeth Kapsch’s Monocacy Aqueduct on the Chesapeake and Ohio Canal tells the aqueduct’s story from its beginnings to present times. It’s available at the C&O Canal NHP’s visitor centers.