Clam Lake Canal
United States
The Clam Lake Canal (sometimes called the Cadillac Canal) is a man-made canal between Lake Mitchell and Lake Cadillac in Cadillac, Michigan, made by George A. Mitchell in the 1870s. The purpose of the canal was to facilitate the movement of logs to sawmills. The canal displays an unusual water phenomenon; it is frozen over in the first part of the winter when the lakes on each side of it are unfrozen. Then when the adjacent lakes freeze, the canal remains unfrozen.
Canal data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).