Places We Protect

Summerton Bog


Tamarack and other trees frame the wetlands under a blue sky during summer at the Summerton Bog State Natural Area.
Summerton Bog Sedges typically found in northern Wisconsin can also be seen at Summerton Bog State Natural Area in south central Wisconsin. © Joshua Mayer

In this protected area, a wide variety of wildflowers proliferate.



Why You Should Visit

Summerton Bog is one of just a few remaining wetland areas of its kind in southern Wisconsin. 

It is unique because Summerton Bog contains plant varieties—sedges, in particular—that are typically northern in type.  

This small, protected area also contains a wide variety of wildflowers along a western section of calcareous fen.  Rising above the willowy grasses is a five-acre oak island that stands in marked contrast to the low vegetation all around.

The wetland preserve is dedicated as a National Natural Landmark and is available for education and research. The fen is located on two sides of a raised oak/hickory upland island, towards the southeast corner of the site.


Very difficult walking conditions throughout the sedge meadow and bog portions of this preserve.  There are 80 acres of uplands along Freedom Road.

Warning: Poison Sumac found throughout the sedge meadow and tamarack bog.

Why TNC Selected This Site

Summerton Bog stands in a glacial lakebed where muck and peat soils support the various wetland types and emergent aquatic communities.  Water is at or near the surface year-round in the lowland areas, supplied by precipitation and five large artesian springs.  The earliest maps of the area, dating back to the 1830s, show sedge meadow as the predominant vegetation.  Subsequent land use for grazing, haying, logging and ditching disturbed the ecosystem, and the meadows are succumbing to an invasion of shrubs or are lost altogether outside the preserve. The Conservancy began acquiring land at Summerton Bog in 1966.




Open year-round, dawn to dusk.


451 acres

Explore our work in this region

What to See: Plants

Some plants common to Summerton Bog:

  • Tussock & sawgrass sedge
  • Aster species
  • Joe-pye-weed
  • Goldenrod
  • Flowers in the fen include fringed gentians, yellow avens, bunchberry, yellow stargrass, yellow loosestrife and lobelia.

What to See: Animals

  • The low, lush meadow and fen vegetation surrounded by tamaracks is a gathering place for nesting birds. As many as 65 species have been spotted.  The Nashville warbler, veery, green heron and the song sparrow are just a few of the birds that reside in season. 
  • The bog is also an important nesting area and migratory stopover for sandhill cranes.
  • The pickerel frog, which was once considered a threatened species in Wisconsin.

All of our preserve maps are now georeferenced. You can download an app on your Apple or Android device, and it will allow you to view your location, record GPS tracks, add placemarks and find places.