Algonquin: The Prehistoric Michigan Great Lake You Never Saw

Try to imagine most of the Upper Peninsula gone...covered in water. It would make a body of water so huge, it would be almost like an ocean. Well, there was such a lake in upper Michigan well over 2 ½ million years ago...it covered the space of Lake Superior, Lake Michigan, Lake Huron, most of the Upper Peninsula, the tip of the Mitten, and a good hunk of Canada.

It was called Lake Algonquin.....a pro-glacial body of water that existed during the last Ice Age. This lake had been around from 2 ½ million to 11,000 years ago.

Marking time from eleven thousand years ago, another four thousand years go by, glaciers subsided and Lake Chippewa and Lake Stanley appeared. Another 3,000 years go by with more glacial melting, and now Algonquin is replaced by the more familiar Great Lakes: Superior, Michigan, and Huron.

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According to The Illinois Glacial Lobe, “Its existence is based on evidence of the establishment and erosion of its outlet through the distributaries of the St. Clair River at St. Clair, and on characters of the Niagara River and gorge. The steps of transition...(are)...made so by the conditions of development from the first stage to the later fully developed Lake Algonquin, which included all three of the upper Great Lake basins.”

And according to Wiki, “the main phase of Lake Algonquin formed across both the Lake Michigan and Lake Huron basins, then overflowing the low lands of Michigan's Upper Peninsula.”

Yeah...as you'll see in the photo below, the Upper Peninsula begins at Marquette (which looks like it was once an island!), with Lake Algonquin covering the whole middle and eastern portions of the U.P, covering all the land which one day would hold Sault Ste. Marie, St. Ignace, Mackinac Island, and even further down to Mackinaw City. Going further west, it also covered most of the Keweenaw Peninsula.

Have a look at the map below and imagine what it would be like to still have that monster lake!