This giant board and its rusted eyelet bolt are found on the tow path of the C&O canal. It is part of a lift lock used to bring canal traffic up hills. The canal ran from Georgetown DC to Cumberland MD from 1850 to 1924 when it was displaced by the railroad. It now belongs to the national park service who do an amazing job of keeping this expensive old ditch full of water and the path clear for bikes, people and dogs. (For people who love this canal as much as I do I think this was lock 15 or 16 between Widewater and Great Falls)