Explore the St. Louis River
Welcome to the St. Louis River, the headwaters of the Great Lakes.
Known to local Anishinaabe as Gichigami ziibi, “the river that flows into the great waters”, this is the home to the world’s largest freshwater estuary.
This place holds a rich and layered human history. For thousands of years, the river has been home to Native American communities and life ways, followed later by European explorers, missionaries, and settlers, and today, by all of us who live, work, and recreate here.
For centuries, human hands have affected the river. Trapping, logging, quarrying, shipping, and steelmaking made permanent changes within the landscape. Yet the river endures. Its wetlands, bays, and shorelines remain a remarkably productive haven for birds, fish, and mammals.
Along the river’s edges, industry and green shoreline exist side by side, a visible reminder that people have always been part of this place. The St. Louis River’s story is one of change, resilience, and responsibility, connecting its past, present, and future in a dynamic and living system.
This website page focuses on the lower St. Louis River estuary, the portion of the river that begins at the Fond du Lac Dam and extends to Lake Superior. This dynamic stretch includes the river’s freshwater estuary, industrial harbor, and coastal wetlands, and highlights the place where river, community, and lake come together.
Location
The St. Louis River, the largest U.S. tributary to Lake Superior, drains 3,634 square miles, entering the southwestern corner of Lake Superior between Duluth, Minnesota, and Superior, Wisconsin. The river flows 179 miles, passing through diverse landscapes that reflect its glacial history - from coarse soils, glacial till, and outwash deposits at its headwaters, to the deep, narrow gorge at Minnesota’s Jay Cooke State Park, and the red clay soils in its lower reaches.
Below the Fond du Lac Dam, the river slows and spreads out as it approaches Lake Superior, forming a 12,000-acre freshwater estuary. This estuary marks the transition between river and lake, where flowing waters meet sheltered bays, wetlands, and coastal habitats.
The upper estuary has some wilderness-like areas, while urban development, an industrial harbor and a major port characterize the lower estuary. The lower estuary includes St. Louis Bay, Superior Bay, Alleous Bay, and the lower Nemadji River. The estuary’s active harbor is the largest and busiest on the Great Lakes and one of the leading bulk-cargo ports in North America.
Due to historical industrial pollution, the St. Louis River Estuary was designated an Area of Concern (AOC) by the International Joint Commission under the U.S.–Canada Great Lakes Water Quality Agreement. Areas of Concern are locations across the Great Lakes that were heavily polluted by past practices of dumping untreated waste on land and into waterways.
Cleanup and restoration of the estuary are guided by the St. Louis River System Remedial Action Plan (RAP), a collaborative effort focused on improving water quality, habitat, and overall ecosystem health. The RAP began in 1989 through a partnership between the Minnesota Pollution Control Agency and the Wisconsin Department of Natural Resources. As part of this work, a Citizens Advisory Committee was formed, which later incorporated as an independent nonprofit organization now known as the St. Louis River Alliance. Many of the original citizen and agency partners remain actively involved in restoration efforts today.
History of the Lower St. Louis River
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Geologic History
The lower St. Louis River was shaped by ancient Canadian Shield bedrock and the advance and retreat of glaciers during the last Ice Age. As glaciers melted and the land rebounded, Lake Superior flooded the river valley, forming today’s freshwater estuary and sheltered harbor.
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Natural History
This remarkably diverse estuary is shaped by red clay soils, rising Lake Superior water levels, and protective baymouth sand bars that create sheltered bays and rare Great Lakes wetland habitats. Despite significant wetland loss and dredging since the 1800s, it continues to support rich plant and wildlife communities, including dozens of fish species and critical habitat for birds and other wildlife.
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Human History
The Fond du Lac region, long known as the “Head of the Lakes,” has been a center of Indigenous life, trade, and travel for thousands of years, with Anishinaabeg communities sustaining villages, seasonal camps, and trade routes along the St. Louis River. Beginning in the 1600s, European exploration, fur trading, missionary activity, and later transportation and settlement reshaped the area, laying the groundwork for the development of the Twin Ports.
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Industrial History
The Lake Superior and Mississippi Railroad and the industries that followed transformed the St. Louis River corridor into a major transportation, manufacturing, and shipping hub, driving rapid growth in Duluth and Superior. Railroads, bridges, logging, mining, shipbuilding, and port development reshaped both the river and the region, leaving lasting economic benefits alongside environmental challenges now being addressed through restoration and cleanup efforts.
Habitat & Critters
The lower St. Louis River supports diverse habitats shaped by natural processes and human influences. Between the Fond du Lac Dam and Lake Superior, the river widens into a freshwater estuary where river and lake waters mix, providing nurseries for fish and wildlife, buffering storms, and filtering pollutants. Water depth, clarity, temperature, sediment, and nutrients all influence aquatic plants and animals, while seasonal rainfall and Lake Superior’s seiche—natural oscillations in water levels—further shape habitats. Surrounding uplands affect erosion and water quality, and wetlands, including marshes, wet meadows, shrublands, mudflats, seeps, and fens, offer food and shelter for fish, birds, mussels, and other species, many of which are unique to the Great Lakes region. Human activities such as dams, dredging, shoreline development, and runoff have altered the river, but these habitats remain vital and highly productive.
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Mammals
Woodchucks, ground squirrels, chipmunks, red squirrels, rabbits, weasels, mice, voles, beavers, muskrats, porcupine, black bears, raccoons, mink, otters, white-tailed deer, skunks, coyotes and red fox are the most commonly seen animals near the St. Louis River.
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Birds
The lower St. Louis River and its environs are home to a diverse array of native animal species. Nearly 300 bird species are commonly found in Minnesota. Over 230 bird species have been documented in the lower St. Louis River. This area is both a critical migratory bird stopover and an important breeding area.
WILL LINK TO SEPERATE WEBPAGE WITH FULL LIST OF BIRDS THAT CAN BE SPOTTED, WHERE TO BIRD MAP FROM AUDUBON, ETC. -
Fish
The most popular fish in the St. Louis River is the walleye. It lives much of the year in Lake Superior, but returns to the river in the spring for spawning. The walleye remains in the river for most of the summer before heading back to the lake for winter. Other game fish such as the muskellunge, northern pike and smallmouth bass, as well as panfish such as crappies, bullheads and yellow perch are year-round residents.
WILL LINK TO MORE INFO, REGULATIONS, LINKS FOR SAFE EATING, STURGEON RECOVERY, ETC.
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Flowering Plants
Cattails, black-eyed susans, clovers, water lilies, milkweed, indian paint-brush, smartweeds, wild rice, buttercups, wild iris, wild roses, arrowhead plants, fringed sedges, pickerel-weeds, trilliums and sumac are flowering plants located on or near the river.
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Trees
Pines such as the red, white, and jack are found along the river; along with white and red burr oaks; red, sugar and silver maples; balsam fir; black and white spruce; basswood; tamarack; white and black ash; quaking and big-toothed aspen; northern white cedar; and paper and yellow birch.
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Mussels
There are several native freshwater mussels found in the lower St. Louis River. Mussels require a firm substrate on which to attach; so far, they have only been documented in the stretch below the Fond du Lac dam, the dredged river channel and the industrial harbor flats. The lower St. Louis River was sampled for mussels in 2000, when eight native species were documented. Non-native zebra and quagga mussels were also present.