It's the only Great Lake entirely within the U.S.
[DOC] [TLE] 10 Deep Facts About the Great Lakes | Mental Floss [PAR] Feb 1, 2016 ... ONLY ONE OF THE LAKES IS LOCATED ENTIRELY IN THE U.S.. As its name 
suggests, Lake Michigan and its 1180 cubic miles of water, 22,300 ... is the only 
one of the Great Lakes that lies entirely within American borders.