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Wisconsin State Natural Areas Program Avon Bottoms (No. 36)

Avon Bottoms

Photo by Thomas A. Meyer/DNR



Within Avon Bottoms Wildlife Area, Rock County. 1,649 acres.



Two distinct units are included in Avon Bottoms SNA: Avon Bottoms floodplain forest and Swenson wet prairie. Large silver maples, swamp white oaks, and green ash dominate the diverse canopy of the floodplain forest. Other tree species are shagbark hickory, hackberry, cottonwood, bitternut hickory, bur oak, American elm, and basswood. Sycamores, at the northern limit of their range, are occasionally present and black willows are common along the river. The forest contains a rich herbaceous and shrub layer with many southern-ranging species found at their northern range limit here. Common shrubs are buttonbush and dogwoods and poison ivy is abundant in two forms –shrub and climbing vine. Other common lianas include wild cucumber, river grape, woodbine, and common moonseed. The composition of the understory differs from other Wisconsin floodplain forests due to the presence of rare southern-ranging plant species. The Swenson Wet Prairie Unit lies in the low, flat floodplain of the Sugar River near its confluence with Taylor Creek. The site contains an excellent example of a wet-mesic prairie and sedge meadow with low river bottom savanna and scrub interspersed with shallow, abandoned river channels. The meadow is dominated by blue-joint grass, big and little blue-stem, Indian grass, and sedges. Numerous forbs include swamp milkweed, white wild indigo, shooting-star, blue flag iris, pale-spike lobelia, cardinal flower, prairie blazing-star, cup plant, Culver's-root, golden alexanders and Michigan lily. There are a number of oxbows – temporary pond areas made by the cut-off of old stream meanders – along with running sloughs and potholes, which all harbor unusual vertebrates and invertebrates. Bird life is diverse with blue-gray gnatcatchers, tufted titmice, blue and green winged teal, and wood ducks. Avon Bottoms is owned by the DNR and was designated a State Natural Area in 1958. In 2016, it was expanded to include Swenson Wet Prairie and more of the high quality floodplain forest along the river.


Driving directions

Numerous parking areas provide access to the floodplain forest. From the intersection of County Highway K and Beloit-Newark Road in Newark, go west on Beloit-Newark Road 4 miles, then south on Nelson Road 1.6 miles to a parking area east of the road and south of the Sugar River.

For Swenson Wet Prairie: From the intersection of State Highway 11 and County Highway T in Brodhead, go south on T 5 miles, then east on Smith Road 0.25-mile to a parking area south of the road. Walk south on the access lane 0.25-mile to the northwest corner of the site.


Avon Bottoms is owned by:

  • WDNR


The DNR's state natural areas program is comprised of lands owned by the state, private conservation organizations, municipalities, other governmental agencies, educational institutions and private individuals. While the majority of 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 own custom map where you can zoom to a specific location, please use the DNR's mapping application.


Management objectives and prescriptions


Very few State Natural Areas have public facilities, but nearly all are open for a variety of 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 and/or under the "Access" 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 detailed topographic map are useful tools for exploring larger SNAs.

Entrance fees: Excepting 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 fee. 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

In general, the activities listed below are allowed on all DNR-owned SNA lands. Exceptions to this list of public uses, such as SNAs closed to hunting, are noted under the "Access" tab above and posted with signs on site.

  • Hiking
  • Fishing
  • Cross country skiing
  • Hunting
  • Trapping

Prohibited activities

Although a handful of sites allow activities like primitive camping (e.g. Lower Chippewa River on sand bars) or horseback riding (e.g. S. Kettle Moraine), the activities listed below are generally prohibited on DNR-owned 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
  • Drones: Flying-related activities, including the use of drones, hang-gliders and model airplanes, are prohibited. Permission may be issued by the SNA Program for the use of drones for educational or research purposes.
  • 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]

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Last revised: Monday, March 27, 2023