11 Most Endangered Historic Places

Monocacy Aqueduct

Year Listed: 1998
Location: Hagerstown, Maryland
Threat: Natural Forces, Public Policy


It was a wonder of 19th-century ingenuity, its seven graceful stone arches carrying the placid water--and the barge traffic--of the busy C&O Canal across the ripples of Maryland's Monocacy River. Since the canal closed in the 1920s, the aqueduct has become a magnet for hikers and cyclists on the towpath in the C&O Canal National Historical Park. But time and the elements were not kind to this engineering landmark. More than a century of floods, coupled with a chronic lack of funds for maintenance, have caused serious deterioration of the structure's stonework. The damage needs to be corrected or the Monocacy Aqueduct could collapse--cutting the C&O towpath in two and breaking an important link with America's past.