Places We Protect

Agassiz Dunes Scientific and Natural Area


in the Agassiz National Wildlife Refuge near Thief River Falls, Minnesota.
Ducks at rest in the Agassiz National Wildlife Refuge near Thief River Falls, Minnesota. © Mark Godfrey

Old, gnarly oaks on high sand dunes carpeted with bluestem grasses makes this a favorite preserve.



Agassiz Dunes is one of our most beautiful preserves, with old, gnarly bur oaks growing on high sand dunes that are carpeted with grama and bluestem grasses.  Visitors can absorb the beauty of the dune area from spring through fall, and of special interest is a grand display of pasque flower in early spring.


Northwestern Minnesota, near Fertile

Why the Conservancy Selected This Site

The Minnesota Natural Heritage Program has identified approximately 74,000 acres of this landscape as ecologically significant. Our goal is to continue to preserve, manage and restore the Agassiz prairies by acquiring additional tracts, restoring grassland buffers, connecting core natural areas, and reducing the threat from exotic species. Cooperation with local citizens and land managers will provide opportunities for public education and field experience in this region.

What the Conservancy Has Done/Is Doing

The preserve was acquired by The Nature Conservancy in 1965 from four area farmers, thanks to contributions from individuals and the McKnight Foundation. Agassiz Dunes was designated a Scientific and Natural Area in 1981, and all the land now is leased to this program. Faculty and students from nearby universities are regular visitors to the site, including groups from University of Minnesota's Itasca Biological Station, which have explored the preserve annually since 1930.

Nearby, the City of Fertile owns 560 acres of sand dunes and is developing the area as an environmental learning center. Between the city land and the preserve is 240 acres of private land that the owner has registered with The Nature Conservancy. The registry agreement has dramatically improved the long-term prospects of this ecosystem.

Prescribed burns and aspen girdling and cutting are among the most important management techniques employed at the preserve. In addition, fencing and firebreaks have been constructed.




1,024 acres

Explore our work in this region

What to See: Plants

According to some recent surveys, the preserve harbors 154 vascular plant species and 31 non-vascular plants. Important plant communities at the preserve are the dry sand savanna and dry sand prairie—plus the unique sand blowouts with bur oak and creeping juniper, a species of special concern in Minnesota. Other species of special concern here include false heather, Louisiana broomrape, mudwort, blunt sedge, and small-leaved pussytoes. Even rarer is Indian ricegrass, an endangered species. Hikers should be careful of poison ivy at Agassiz Dunes.

What to See: Animals

Agassiz serves as home to 30 butterfly species, 69 bird species, 14 types of mammals, three species of reptiles, and one amphibian species. The preserve originally supported the poweshiek skipper, a now federally endangered species, but it has not been documented here in recent years. Visitors may hear the vesper sparrow or spot the upland sandpiper, or the plains pocket gopher, a species of special concern. The landscape is also a regional stronghold for the greater prairie chicken, a year-round resident.

Preparing for Your Visit

Download a 1-page fact sheet here.

For more information on visiting this and other Minnesota preserves, check out our Preserve Visitation Guidelines.