Places We Protect

St. Louis River


Aerial view of a broad river with islands in it covered in trees showing some fall colors.
St. Louis River Estuary Aerial of St. Louis River Estuary, the largest Great Lakes estuary in the U.S. © Richard Hamilton Smith

The St. Louis River is the largest U.S. tributary to Lake Superior.



The Nature Conservancy has worked to protect the St. Louis River from its headwaters in Minnesota's Northwoods to where it flows into Lake Superior and forms a 12,000-acre freshwater estuary—like none other in the Great Lakes.

The St. Louis River originates north of Two Harbors, Minnesota and flows through some of the region's best lowland conifer forest and peatland for 179 miles before it meets Lake Superior above the twin ports of Duluth and Superior to form the St. Louis River Estuary.

The combination of ecosystems within the Estuary—estuarine wetland and aquatic habitats, baymouth bar complex, its importance to breeding and migratory birds, and its importance to native fish—are very unusual in Lake Superior, the Upper Midwest, the Great Lakes, and around the world.

What the Conservancy Has Done/Is Doing

Threats to the Estuary include loss of habitat due to development, commercial shipping and other sources, increased sedimentation due to development, forest management practices and other sources, competition from undesirable exotic species introduced by commercial shipping and development, exposure to contaminants from historical and current industrial activity, and water quality.

In 2002, the Conservancy assisted the City of Duluth in developing a new law establishing the Duluth Natural Areas Program, which designates for protection special natural areas owned by the city (a major landowner in the Estuary).

To help lake sturgeon recover in the St. Louis River, the Conservancy helped the Minnesota Department of Natural Resources improve spawning habitat for this ancient fish, which can reach a length of more than six feet and live more than 100 years.

In 2010, the Conservancy protected Clough Island, the largest island within the St. Louis River Estuary. The island's size and prominent location make invaluable for wildlife including migratory and breeding birds as well as fish that move between Lake Superior and the river.

The Conservancy also assisted in the effort by Minnesota and Wisconsin fisheries staff to estimate the lake sturgeon population in the river and western Lake Superior by purchasing passive integrated transponder or PIT tags, similar to the ones placed under the skin of pets, that were inserted into approximately 200 adult lake sturgeon. The tags were purchased by the Conservancy thanks to a grant from the Biodiversity Fund of the Duluth Superior Area Community Foundation.

Others that are working to restore the St. Louis River Estuary include:

  • St. Louis River Alliance
  • Minnesota Department of Natural Resources
  • Wisconsin Department of Natural Resources
  • Minnesota Land Trust
  • Minnesota Sea Grant
  • Fond Du Lac Band of Lake Superior Ojibway
  • U.S Environmental Protection Agency
  • City of Duluth
  • City of Superior
  • Minnesota Power
  • Minnesota Ornithologists’ Union
  • U.S. Coast Guard
  • U.S. Fish and Wildlife Service
  • Natural Resources Research Institute – UMD
  • Minnesota Pollution Control Agency
  • Carlton County Soil and Water District
  • 1854 Authority
  • Douglas County
  • Numerous private citizens and companies

Today, the Conservancy's work on the St. Louis River is focused largely on its headwaters within the Sand Lake/Seven Beavers landscape. The Conservancy owns and manages more than 6,000 acres and is working with partners to protect and restore more of the region's lowland conifers and sensitive aquatic communities.



Explore our work in Minnesota

What to See: Plant Communities

The St. Louis Estuary includes a wide variety of plant communities. Aquatic plants, found in the wetlands and riverine systems of the Estuary, generally are adapted to fluctuations in water levels caused by the seiche (back and forth sloshing) of Lake Superior. Upland forest plants include northern hardwood forests at Magney-Snively Park with spring ephemeral plants and old growth forests, and aspen-spruce-fir forests in Superior Municipal Forest. The baymouth bars of Wisconsin and Minnesota (Park) points include sensitive beach dune plant communities as well as old growth upland red pine forests. 

What to See: Animals

Birds and fish are the biggest attraction, although the area also is home to black bear, wolves, mink, otters, white-tailed deer and red fox. The St. Louis Estuary serves as the primary nursery for the fish found in western Lake Superior, and is home to over 45 native fish species, including walleye, lake sturgeon, muskellunge, northern pike and smallmouth bass. There are also several species of native freshwater mussels found in the Estuary.

The St. Louis Estuary is home to over 230 bird species and is a critical migratory stopover and breeding area. In addition to a multitude of songbird species, large numbers of raptors, shorebirds, waterbirds, gulls, and terns migrate through the area each spring and fall. Several factors make the Estuary an important stopover site. Many migrants will not fly over large bodies of water and thus are funneled to the Estuary at the far western end of Lake Superior. The Estuary contains large expanses of wetlands that provide important food sources and nesting habitat. The Estuary also is a rarity in that it includes open, sandy beaches for shorebirds. The diversity of habitats make the St. Louis Estuary ideal for breeding birds as well.

While the Conservancy currently owns two properties within the estuary, its efforts here focus more on working with existing landowners, such as the City of Duluth, to protect special natural areas. The estuary is easily appreciated by foot or by boat, with numerous trails and quiet waters and entry points on both sides of the estuary.

Visitors are encouraged to explore Jay Cooke State Park, Magney-Snively Park and Spirit Mountain, North Bay, Superior Municipal Forest (4000 acres), Park Point and Wisconsin Point.