The Lake Superior National Estuarine Research Reserve includes land and water areas along the St. Louis River and Lake Superior in Douglas County, in the northwest corner of Wisconsin, United States. It is one of 29 National Estuarine Research Reserves. The Reserve is operated as a program of the Natural Resources Institute of the University of Wisconsin-Madison Division of Extension. It has an area of , and was designated in 2010. Location The Lake Superior Reserve is situated on the westernmost tip of Lake Superior, and represents portions of the lower St. Louis River freshwater estuary within the state of Wisconsin. The St. Louis River is the largest United States tributary to Lake Superior and flows through a watershed within Wisconsin and Minnesota, eventually creating of the boundary between the two states. Diversity The site is diverse and includes the following representative ecosystem types: maritime forest-woodland (northern coniferous biome, temperate deciduous forest biome), coastal shrublands, coastal grasslands, coastal marshes and coastal swamps. The hydrographic characteristics of the site include stratified circulation, with a tide type dominated by wind/storm tides and related seiche (sometimes called “slosh”). Surface water runoff from the St. Louis River watershed is the primary source of freshwater into the estuarine system. The Reserve includes areas of national significance, including the world’s largest freshwater bay mouth sand bar (Wisconsin Point), estuarine wetlands, and steep highly erodible red clay bluffs. Significant historic and cultural sites exist within or adjacent to the boundary including Native American cultural sites throughout the estuary and on Wisconsin Point and historic lumbering and shipping sites along the estuary’s shore. The wetlands of the St. Louis River freshwater estuary form one of the largest complexes of estuarine wetlands in the Lake Superior Basin. The coastal wetland complex is a mosaic of varying combinations of submergent marsh, emergent marsh, wet meadows or fens, and wet shrublands. Two Wisconsin State Natural Areas (SNAs) and 11 Wisconsin Priority Wetlands are found within the boundaries. Recently, Priority Conservation Opportunity Areas were identified for Wisconsin’s Wildlife Action Plan. Through that process, the wetlands and boreal forest associated with the St. Louis River freshwater estuary complex were identified as an area of continental significance. While some portions of the Reserve have been influenced and altered by human activities, the many designations and recognitions of valuable habitats within the St. Louis River freshwater estuary complex clearly indicate that there are portions that