Pilot Knob State Preserve

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State Preserves

Pilot Knob State Preserve is a 238-acre area in Pilot Knob State Park, four miles east of Forest City in northeastern Hancock County. 

It features a “poor fen” and an extensive forest on a prominent hill associated with the Algona and Altamont moraines. 

In 1921, a group of local citizens purchased land around Pilot Knob and donated it to the state. The Iowa Conservation Commission established this area as a state park in 1924. In 1968, a large portion of the park was dedicated as a biological state preserve. 

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About the Land

Located in the Des Moines Lobe landform region, Pilot Knob is a classic glacial kame. These distinct features are large, steep-sided, often conical hills composed of sand, gravel, and small boulders. 

This material was carried by a meltwater stream that poured off the edge of a stagnant ice front or into a large hole in the disintegrating ice. Bowl-shaped depressions (“kettles”) in the landscape result from melting of partially buried blocks of glacial ice. 

The Winnebago River was a drainage outlet during melting of the Algona ice front between 13,500 and 12,000 years ago. The Pilot Knob Member of the Wisconsinan-age Dows Formation is named for this site. 

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Directions

  1. From the intersection of Highway 30 and I-35 on the east side of Ames, take I-35 north 2 miles to the 13th Street exit (exit 113). 
  2. Go west (left) 2.5 miles to Grand Avenue. Turn north (right) and go 0.5 mile to 20th Street. 
  3. Turn west (left) and drive 1 mile into the Ames High School parking lot. 
  4. There is a small parking area near the preserve on the west side of the high school (sign: Richard W. Pohl Memorial Preserve at Ames High Prairie).
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Plants

Over 420 plants have been found throughout the preserve in several plant communities. Most of the preserve consists of dry upland forest dominated by bur oak and northern pin oak. A small grove of white oak also occurs in the southeastern portion of the preserve. 

Mesic forests on some northfacing slopes are dominated by red oak and basswood. 

Common in the understory are:

  • Ironwood
  • Hazelnut
  • Ash
  • Elm

Snow trillium, bloodroot, hepatica, and rue anemone can be seen as early as March, joined later by:

  • Downy yellow violet
  • Woodland sedge
  • Wild ginger
  • Dutchman’s breeches
  • Bellwort
  • Showy orchis
  • Wild geranium
  • Nodding trillium
  • Blue cohosh
  • Wood anemone
  • Ladies’ tobacco
  • Jack-in-the-pulpit
  • White trout-lily 

Summer flowers include wild leek, wild sarsaparilla, white avens, and purple joe-pye-weed. By fall, zigzag goldenrod, smooth goldenrod, blue wood aster, and Ontario aster are blooming. 

Many ferns are found in the forest throughout the year. 

Dead Man's Lake

Dead Man’s Lake is located in a 15-acre depression in the southwestern corner of the preserve. The east half of the lake is mostly open water surrounded by a narrow fringe of wetland vegetation composed largely of cattails, bulrushes, and willows, but the western half is a floating mat. 

More properly termed a “poor fen,” this boggy habitat is comprised of nearly a continuous mat of Sphagnum moss. Several rare plants in Iowa occur only here, including sundew and cordroot sedge. 

Other rare species in the bog include bog willow and slender cottongrass. 

Marshes

The marshes that are scattered throughout the preserve in the poorly drained depressions are dominated by sedges, bulrushes, and spikerushes. 

Other plants commonly found along these marsh edges include:

  • Horsetail
  • Arrowhead
  • Smartweed
  • Marsh muhly
  • Rice cutgrass
  • Prairie cordgrass 

Ferns include marsh fern, sensitive fern, and crested fern. 

Many plants bloom through the seasons beginning with spring cress and extending progressively through the summer with:

  • Blue flag iris
  • Giant bur reed
  • Swamp loosestrife
  • Monkey flower
  • Marsh bellflower
  • Swamp milkweed
  • Northern bugleweed
  • Bulblet water hemlock 

Great lobelia and nodding bur marigold fill out the fall season. 

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Visitor Information

Pilot Knob State Park is listed on the National Register of Historic Places for its significant Civilian Conservation Corps facilities. 

Hunting is not permitted. 

Other natural areas in the vicinity include Gabrielson Wildlife Area and Hoffman Prairie State Preserve.

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