I think the indians around the lake call it “gitchee gumee”....thw witch of november in the song refers to a time in november i think 1913 where a large amount of boats were lost in storms...
...was the witch of November come stealin’..great lyrics..typical of Lightfoot..
It's a Chippewa (Ojibway) phrase. Means "great waters." It's also mentioned in Longfellow's poem "Hiawatha." By the shores of Gitchee Gumee, by the Shining Great Sea Water ..."