Upper Mississippi River

Upper Mississippi River National Wildlife and Fish Refuge stretches 261 miles along the Mississippi River from Wabasha, Minnesota to Rock Island, Illinois, protecting more than 240,000 acres of Mississippi River floodplain across four states. Wisconsin contains approximately 89,638 acres of the refuge, the largest share of any state, encompassing vast expanses of river bottomland along the state's western border. Established in 1924, it is one of the oldest national wildlife refuges in the country and ranks as the most heavily visited refuge in the nation, drawing over 3.7 million annual visits for fishing, hunting, wildlife observation, and boating.

The refuge supports one of the most diverse wildlife assemblages in the Upper Midwest, with its mosaic of aquatic, wetland, and forest habitats providing resources for hundreds of species throughout the year. More than 300 pairs of bald eagles nest along the refuge, taking advantage of one of the largest contiguous blocks of floodplain forest in the lower 48 states. The Mississippi Flyway funnels millions of migratory birds through the corridor each spring and fall, including massive concentrations of canvasback ducks, tundra swans, and various dabbling duck species. Muskrats, beavers, river otters, white-tailed deer, and wild turkeys are among the common resident mammals and birds, while the river supports more than 120 species of fish including walleye, sauger, largemouth bass, and paddlefish.

The refuge's vegetation communities reflect the dynamic floodplain environment of the Upper Mississippi River, where periodic flooding, ice scour, and sediment deposition create a constantly shifting mosaic of habitats. Floodplain forests dominated by silver maple, cottonwood, river birch, and green ash line the main channel and backwater areas, providing essential nesting habitat for bald eagles, wood ducks, and numerous songbird species. Emergent marshes of cattail, bulrush, wild rice, and arrowhead occupy the shallow backwater pools and side channels that are among the most biologically productive areas of the refuge. Submergent aquatic vegetation including wild celery, coontail, and various pondweeds provides critical food resources for diving ducks during fall migration.

The Upper Mississippi River valley was carved through the landscape over millions of years, with the current river course largely established following the drainage of glacial Lake Agassiz approximately 9,000 years ago, which sent enormous volumes of meltwater down the Mississippi corridor. The Wisconsin portion of the refuge lies at the boundary between the Driftless Area and glaciated terrain, where the river's broad floodplain occupies a valley cut deeply into Paleozoic-era sandstone, dolomite, and limestone bedrock. The construction of a series of navigation locks and dams by the U.S. Army Corps of Engineers in the 1930s fundamentally altered the river's hydrology, creating the extensive backwater pools and marshes that characterize today's refuge landscape. Sediment deposition behind these dams continues to reshape the floodplain, gradually filling backwater habitats and creating new management challenges.

The Upper Mississippi River corridor experiences a humid continental climate with significant seasonal temperature variation, from summer highs in the upper 80s to low 90s Fahrenheit to winter lows frequently below zero. Annual precipitation averages 30 to 34 inches along the Wisconsin portion, with spring snowmelt and rain events producing the river's highest water levels typically from March through June. Winter ice formation on the river and backwaters creates important habitat for some species while restricting access for others, and the timing of ice-out in spring is a key ecological event that triggers fish spawning, bird migration, and vegetation growth. Severe weather events including thunderstorms, tornadoes, and major flooding can dramatically impact refuge habitats, with the record floods of 1965, 1993, and 2019 causing widespread inundation and habitat reorganization.

The Upper Mississippi River has served as a major transportation corridor and resource for human communities for at least 12,000 years, with evidence of Paleo-Indian, Woodland, and Mississippian cultures throughout the river valley. Dakota, Ho-Chunk, and Sauk peoples maintained settlements and seasonal camps along the river, fishing, hunting, and harvesting wild rice from the extensive backwater marshes. French explorers including Louis Joliet and Father Jacques Marquette traveled the river in 1673, opening it to European fur trade and eventually settlement. The 19th century brought steamboat commerce, lead mining, and commercial fishing that dramatically increased human impact on the river ecosystem, while industrial pollution and navigational engineering transformed the river's character in the 20th century.

The Upper Mississippi River National Wildlife and Fish Refuge was established on June 7, 1924, through an act of Congress championed by Will Dilg and the newly formed Izaak Walton League of America, along with the Federation of Women's Clubs of America, who were alarmed by a proposal to dike and drain the river floodplain for agriculture. The refuge was among the first to be designated specifically for fish as well as wildlife, reflecting the importance of the river's fisheries. In the 1930s, the U.S. Army Corps of Engineers constructed a system of 29 locks and dams along the Upper Mississippi for navigation, which flooded portions of the refuge but also created the extensive backwater habitats that now support enormous waterfowl concentrations. The refuge celebrated its centennial in 2024, marking 100 years of protecting one of America's most important freshwater ecosystems.

The Great River Road, a National Scenic Byway that parallels the Mississippi River through Wisconsin, provides access to numerous refuge overlooks, boat landings, and wildlife viewing areas along the state's western border. Observation decks at several locations offer elevated views across backwater pools and marshes where waterfowl, eagles, and wading birds can be observed, particularly during spring and fall migration. Fishing is the most popular recreational activity, with anglers pursuing walleye, sauger, bass, and panfish from boats and shore throughout the refuge. The annual tundra swan migration in late October and November draws wildlife enthusiasts from across the region, as thousands of these majestic white birds rest and feed in the refuge's backwater pools.

The refuge maintains visitor contact stations and offices in multiple locations along its 261-mile length, with the primary Wisconsin visitor center at the Upper Mississippi River Visitor Center in Onalaska providing exhibits, programs, and information. Numerous public boat landings provide water access throughout the Wisconsin portion of the refuge, essential for reaching the islands, backwaters, and marshes that comprise much of the refuge's acreage. The Great River Road connects riverside communities including La Crosse, Prairie du Chien, and Cassville, all of which offer lodging, dining, and outfitting services. The refuge is open daily from sunrise to sunset, with hunting and fishing permitted during designated seasons under federal and state regulations.

Managing the Upper Mississippi River refuge requires balancing the competing demands of navigation, flood control, recreation, and wildlife habitat within a heavily engineered river system. Sedimentation behind the lock and dam system is the single greatest long-term threat, gradually filling the backwater habitats that millions of migratory birds depend upon, and the Fish and Wildlife Service works with the Army Corps of Engineers on habitat rehabilitation projects to maintain these critical areas. Invasive species including Asian carp, zebra mussels, Eurasian watermilfoil, and purple loosestrife pose ongoing ecological challenges that require coordinated management across state and federal jurisdictions. Water quality improvement efforts target agricultural runoff and nutrient loading from the river's vast drainage basin, which contributes to the Gulf of Mexico dead zone and degrades local aquatic habitats.