Glen Lake, with its remarkably blue waters, is famous for its beauty. The lake appears divided into two parts by the constriction at the “narrows” bridge. The two parts are Little Glen Lake in the foreground, only 12 feet deep, and Big Glen Lake, beyond the M-22 bridge, about 130 feet deep. Glen Lake used to be connected to ancestral Lake Michigan. Glacial erosion carved out both lakes during the Ice Age. In post-glacial times, a sand- bar developed, separating Glen Lake from Lake Michigan. Both the D.H. Day Campground and the village of Glen Arbor are located on that sandbar. The flat terrain and proximity to Lake Michigan made it a desirable site for these developments.
The Hill on the north (left) side of Little Glen Lake is called Alligator Hill because of its shape. It is a product of the Ice Age and early post-glacial times. Glaciers carried a tremendous load of sand, gravel and other rock debris frozen in the ice. When the ice melted, the run-off streams deposited great piles of sediment to form the hill. Imagine how thick the ice must have been to have left hills of debris several hundred feet high. The “snout” of the alligator is a wave-cut terrace of a lake that occupied the Glen Lake basin briefly during deglaciation.