For thousands of years before European settlement, Native Americans used Michigan's waterways as an ancient highway, traveling in birch-bark and dugout canoes along the River Raisin, whose higher, more stable flow once made it navigable far into its upper reaches. They portaged canoes overland between rivers, and the River Raisin and Huron River formed important connections from Lake Erie to the Grand, Kalamazoo, and St. Joseph Rivers, leading eventually to Lake Michigan. Near Sharon Mills, the River Raisin's riparian zone marks the meeting of land and water ecosystems in a changing floodplain that helps clean water, supports wildlife, cools streams for fish, reduces erosion, and slows floodwaters. Although many riverside areas have been altered by human activity, including dams that reduced flooding and places where riverbanks were cleared, the woods along the back of the picnic area at Sharon Mills remain the park's best example of riparian vegetation. Wildlife associated with this riparian zone includes great blue herons, yellow warblers, white-tailed deer, common muskrats, and painted turtles.