Routes ran from the French River south to the Jesuit Huron missions at the southern end of Georgian Bay (1626–1640), west through the Strait of Mackinac to Lake Michigan, or west north of Manitoulin Island and up the St Marys River (26 feet difference in elevation) to Lake Superior. On Lake Superior voyageurs would normally hug the northern shore because of the danger of frequent squalls that could overturn their boats.
