The Canal, as complete as it was to be in 1850, 180 miles to Cumberland, Maryland, operated until 1924 when, after being devastated again by a flood such as had plagued the Canal through its history, it closed. The Federal Government acquired it in 1938; becoming the Chesapeake and Ohio Canal National Historical Park in 1971.

Time, weather, and flood took their toll on the Monocacy River aqueduct. After the destruction wrought by Hurricane Agnes in 1973, the Army Corps of Engineers stabilized it with exosketetal steel bracing. Under two consecutive IDIQ contracts with the National Park Service, architrave had several projects, study through construction, to stabilize the aqueduct in a way to eliminate the steel bracing, infill missing railings, provide protection against future damage, and return the aqueduct close to its original and historic appearance.