Native Americans called this river Nummasepee, or River of Sturgeon, after the great fish that once thrived here, and the first French-speaking settlers called it Rivière Aux Raisins, or River of Grapes, for the wild grape vines along its banks. Now known as the River Raisin, it winds from its headwaters in the Irish Hills to its mouth in Monroe, providing habitat for at least 90 species of fish as well as many kinds of insects, birds, and mammals, and over the years it has been important for drinking water, farming, transportation, powering mills, and recreation. Thousands of years ago, glaciers more than a mile thick covered the Great Lakes region, and their advance and retreat carved the lakes, valleys, hills, and rivers seen today; the land here was once the bottom of ancient Lake Erie, and as lake levels fell, the River Raisin formed and extended eastward through the lake plains to empty into Lake Erie. Its watershed includes all the land draining into the interconnected streams connected to the river, covering parts of six counties in two states, and understanding how actions on the land affect the water is important to maintaining healthy rivers. Its floodplain is the flat land beside the river that is sometimes covered by flood waters, where plants are adapted to standing water but buildings and homes are safer on higher ground. In January 1813, about 15 miles downstream, one of the bloodiest battles of the War of 1812 was fought on the river's banks; American forces suffered a major defeat by the British, and the massacre of wounded soldiers the next day outraged Americans and inspired the rallying cry "Remember the Raisin." Among the first people to explore the river were French-Canadian voyageurs, fur traders and outdoorsmen who lived from the abundant wild game of the Great Lakes and the St. Lawrence. People working to keep rivers clean and healthy focus on the entire watershed, and watershed councils, including the River Raisin Watershed Council, develop management plans, protection strategies, and other guidance to promote water quality.