Places We Protect

Jacobson Fen

South Dakota

Large sign that reads Jacobson Fen Preserve with rolling prairie landscape in the background.
Jacobson Fen Jacobson Fen Preserve, located near Clear Lake, South Dakota. © Tom Landwehr

Tallgrass prairie sweeps across this rolling land and unique wetlands communities thrive.



The Jacobson Fen is part of an expansive 18,000-acre mosaic of tallgrass prairie, pothole wetlands, perennial creeks and fen communities and lies at the head of one Monighan Creek’s major tributaries. At this preserve, tallgrass prairie sweeps across this rolling land and unique wetlands communities, specifically fens, thrive.

The mineral-rich water flowing through this region intersects with the surface of the ground, creating the unique characteristics necessary to form a fen. There are roughly 50 fens in the area, with 10 occurring specifically at the Jacobson Fen preserve. Each of these fens produces a unique and complex habitat, and with 55-degree waters that never freeze, important winter habitat for birds and small mammals is created.

Why the Conservancy Selected This Site

Jacobson Fen lies in the heart of a wetland-fen complex. Fens are rare habitats in this landscape, and their protection is critical to sustaining the region’s biodiversity. With perennial flow into Monighan creek, the fens are an important component of the Crystal Springs region. Careful land management here is critical in sustaining species diversity. As a community partner, the Conservancy now is in the position to help guide conservation actions for this rare resource.

What the Conservancy Has Done/Is Doing

In addition to working with the community to conserve this rare landscape, the Conservancy is working to maintaining the diversity of life found here.

Through controlled fires and work to combat harmful, non-native plants, the Conservancy is working to maintain the delicate balance that exists in this ecological community.




160 acres

Explore our work in South Dakota


Jacobson Fen boasts tremendous plant life, in part, because of the fens. Each groundswell of water creates microhabitats for fen related plants. At times, a plant may be unique only to one particular fen, spawning a tremendous diversity of plant life.


Many grassland nesting birds find refuge here, including the sharp-tailed grouse. Many of these birds are experiencing declines as precious grassland habitat has been lost. Jacobson Fen also is a great place to view raptors, or birds of prey. They can be seen various times of year, such as during migration periods. Rough-legged, ferruginous, red-tailed and Swainson's hawks, northern harriers, American kestrel, prairie falcon, great horned and snowy owls all have been observed in this area.

Plan Your Visit

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