Yes, Pirates in the Great Lakes was actually a thing, in fact historians say that the Great Lakes Pirates were some of the most fearsome.

These swashbucklers made their living sailing around our great lakes sailing and searching for treasure.  The treasure these pirates were after included lumber, which they would sell to industrialized Cities, alcohol , which they would sell in the Detroit and Chicago and trade for guns.

One of the more memorable Pirates from  the 1700's was Jack Rackham, or Calico Jack as he was known by, ( because of the colorful clothes that he wore).  Jack would steal anything and everything from cash box's to entire ships.

One of the most notorious pirates on the Great Lakes was Dan Seavey.  Seavey started  out as a regular sailor in the U.S Navy and after he left the military he found himself broke with only his ship to his name.   So he took up a life of plundering and later he made a name for himself by being the only man to be charged with Piracy on the Great Lakes.  After retiring from his life of crime on the lakes, Seavey died in a Wisconsin Nursing Home at the age of 84.