Plagge Woods is an old-growth northern mesic forest perched atop a monadnock, an isolated rock of conglomerate and quartzite rising 3-400 feet above the countryside. The forest is dominated by sugar maple, basswood, and red and white oak, which covers both the north and south slopes on the southeastern edge of the Flambeau Ridge. The forest has a wide range of trees, from seedling and sapling maples to the canopy layer of mature trees, some more than 30 inches in diameter at breast height (dbh). A few white pines on the north side of the tract are in the 3-foot dbh class. Ground layer species are typical mesic woodland plants which include bedstraws, large-leaved aster, golden saxifrage (in springs), baneberries, miterworts, spring beauty, Canada mayflower, wild geranium, and violets. The site was donated by Henry and August Plagge. Plagge Woods is owned by the DNR and was designated a State Natural Area in 1975.