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Deansville Fen

No. 311


Photo by H. Iltis


Located on the western edge of Deansville Marsh Wildlife Area, Deansville Fen is an extensive wetland complex of native plant communities featuring a high-quality calcareous fen grading into wet-mesic prairie and sedge meadow. The ground is hummocky and moderately wet with sedges such as tussock sedge, fen star sedge, and cotton grass, numerous types of grass including blue-joint grass and big blue-stem, and widely scattered shrubs.

The fen contains many rare and unusual plant species that thrive in the carbonate-rich soils including grass-of-Parnassus, Kalm's lobelia, valerian, and Riddell's goldenrod. The area also harbors rare plants. Other species are fowl manna-grass, marsh marigold, turtlehead, spring-cress, northern bedstraw, swamp lousewort, marsh milkweed, and marsh aster. The wetland is also home to a diversity of rare and uncommon birds. Deansville Fen is owned by the DNR and was designated a State Natural Area in 1996.

Very few State Natural Areas have public facilities, but nearly all are open for various recreational activities as indicated below. Generally, there are no picnic areas, restrooms, or other developments. Parking lots or designated parking areas are noted on individual SNA pages and maps. Trails, if present, are typically undesignated footpaths. If a developed trail is present, it will normally be noted on the SNA map under the Maps tab. A compass and topographic map or a GPS unit are useful tools for exploring larger, isolated SNAs.

The good majority of SNAs are isolated and have few or no facilities. Some SNAs have vehicle access lanes or parking lots, but their accessibility may vary depending on weather conditions. Parking lots and lanes are not plowed during winter. Hiking trails may be nonexistent or consist of undeveloped footpaths. A GPS unit or compass and a detailed topographic map are useful tools for exploring larger SNAs.

Entrance fees: Except for Parfrey's Glen, the Cambrian Outlook in the Dells of the Wisconsin River, SNAs within State Parks and some within State Forests, all other DNR-owned SNAs do not have any admission fees. For more information, see Wis. Admin. Code NR 45. For non-DNR-owned SNAs, we are unaware of any vehicle or admission fees. However, please contact the landowner for more information.

Allowable activities: DNR-owned land

The activities listed below are generally allowed on all DNR-owned SNA lands. Exceptions to this list of public uses, such as SNAs closed to hunting, are noted above and posted with signs on the property site.

  • Hiking
  • Fishing
  • Cross country skiing
  • Hunting
  • Trapping
  • Scientific research (permit required)
  • Outdoor education
  • Wild edibles (What is this?)
  • Pets (Rules)
  • Wildlife viewing

Prohibited activities: all SNAs

  • Camping and campfires
  • Collecting of animals (other than legally harvested species), non-edible fungi, rocks, minerals, fossils, archaeological artifacts, soil, downed wood, or any other natural material alive or dead.
  • Collecting for scientific research requires a permit issued by the DNR
  • Collecting of plants including seeds, roots or other non-edible parts of herbaceous plants such as wildflowers or grasses
  • Geocaching
  • Horseback riding
  • Rock climbing
  • Vehicles, including bicycles, ATVs, aircraft, and snowmobiles except on trails and roadways designated for their use.

For rules governing state-owned SNAs and other state lands, please consult Chapter NR 45 Wis. Admin. Code [exit DNR].


Dane County. T9N-R11E, parts of sections 25, 36. T9N-R12E, parts of sections 30, 31. 604 acres.

Driving directions

From the intersection of State Highways 73 and 19 in Marshall, go west on 19 for 4.7 miles, then north on Twin Lane Road for 3.3 miles, then east on Greenway Road for 0.7 miles to a parking area. Walk 0.4 miles east, then south and cross the Maunesha River to the fen.

The DNR's state natural areas program comprises lands owned by the state, private conservation organizations, municipalities, other governmental agencies, educational institutions, and private individuals. While most SNAs are open to the public, access may vary according to individual ownership policies. Public use restrictions may apply due to public safety, or to protect endangered or threatened species or unique natural features. Lands may be temporarily closed due to specific management activities.

Users are encouraged to contact the landowner for more specific details. The data shown on these maps have been obtained from various sources, and are of varying age, reliability, and resolution. The data may contain errors or omissions and should not be interpreted as a legal representation of legal ownership boundaries. To create your custom map where you can zoom to a specific location, please use the DNR's Mapping Application.

Property map [PDF]


Deansville Fen is owned by: Wisconsin DNR