Mill Bluff State Natural Area

Mill Bluff State Natural Area features a number of spectacular Cambrian sandstone mesas, buttes, and pinnacles that rise above the level bed of ancient Glacial Lake Wisconsin. Long Bluff, Ragged Rock, Wildcat Bluff, Bear Bluff, Devil’s Monument, Camel’s Bluff, Mill Bluff, and Round Bluff are all included within the Area. Many of the bluffs contain 6-12 inches long petroglyphs (rock carvings) that are shaped like bird tracks. Similar to the petroglyphs found 25 miles east in Roche-A-Cri State Park, they date back to Upper Mississippi Indian culture about 400 years ago.  

The dominant plant community is a xeric (dry) forest composed primarily of Hill’s oak, Jack pine, red pine, white pine, and white oak. Associated trees include big-tooth aspen, black cherry, red oak, paper birch, and red maple. Many of the sandstone outcroppings contain large red pine. On Long Bluff, the dominance of different trees varies, with oak and pine more prevalent on the western and southern exposures while red maple is more common on the east side of the bluff, especially on the lower slopes. Low shrubs including early low blueberry, huckleberry, sweet gale, plus bracken fern and Pennsylvania sedge characterize the groundlayer. A few prairie and barrens plant species are present especially on the flats at the base of the bluff’s west end. Plants include big blue-stem, little blue-stem, Indian grass, wild lupine, lyre-leaved rock cress, bird’s-foot violet, and common rock-rose.

Birds include turkey vulture, wood thrush, rufous-sided towhee, eastern wood pewee, ovenbird, yellow-throated vireo and clay-colored and vesper sparrows.

The site is managed as an oak-pine barrens preserve, a Karner Blue butterfly restoration site (a federally endangered butterfly), a significant archaeological and geological site, and an ecological reference area.

Mill Bluff is owned by the DNR and was designated a State Natural Area in 2002.

Source: WDNR