Heading upstream from Georgetown, the Antietam Creek Aqueduct is the fourth of the C&O Canal’s eleven aqueducts. It is a 140′, three span structure that was completed in 1834, and for being 179 years old, it is in remarkably good condition. A side-by-side comparison between this aqueduct and the one over Conococheague Creek is pretty remarkable. Both streams are among the Potomac’s largest tributaries on the Maryland side between Cumberland and Georgetown, and both aqueducts have three arches. However, the Conococheague is backed up from the Potomac, while the Antietam is free-flowing and shallow, and there isn’t nearly as much debris to contend with. Likewise, flooding doesn’t appear to be as big of an issue as it is in Williamsport.
Considering that the Catoctin Creek Aqueduct has been rebuilt and Monocacy has underwent extensive repairs, the Antietam Aqueduct has survived the ravages of nature–perhaps–better than any of the larger structures on the C&O Canal. Seneca Creek is missing an arch, and (to the best of my recollection) all of the single-arch aqueducts on the northern (or western, depending on who you ask) end of the canal are missing their upstream walls. Why the Antietam Aqueduct has endured so well is beyond me, but it appears that the lay of the land might have something to do with it. Likewise, a lot of credit has to be given to the stone masons and laborers who built this magnificent aqueduct. It really is something to see!