Which waterway, Chain of Rocks Lock or Dismal Swamp Canal, is the oldest continually operating man-made canal in the United States?
Chain of Rocks Lock: Chain of Rocks Lock, also known as Locks No. 27, is a lock situated at the southern end of Chouteau Island near St. Louis, Missouri on the Upper Mississippi River. Dismal Swamp Canal:  It is the oldest continually operating man-made canal in the United States, opened in 1805, and closed in October 2016.
i don't know