The answer is East of Lake Michigan. It was shaped by dissolving ice as the mainland icy masses withdrawn toward the finish of the last ice age. Prior to this, Lake Huron was a low-lying gloom through which streamed the now-covered Laurentian and Huronian Rivers; the lake bed was bungled by a vast system of tributaries to these antiquated conduits, with a hefty portion of the old channels still clear on bathymetric maps.
