Black Tern Bog consists of two small seepage lakes in a pitted outwash plain and contains an outstanding flora including several rare and unusual species. About 20 acres of quaking sphagnum bog surround the bog pools and contain such characteristic species as sundew, pitcher plant, bladderwort, buckbean, bog-laurel, bog-rosemary, leather-leaf, and cotton grass sedge. Of special interest are uncommon plants including swamp pink, rose pogonia, grass pink, and a state endangered rush. Dwarf white pine and black spruce are found on the bog with second growth hardwoods surrounding it. Nesting bird species include killdeer, common snipe, mallard, song sparrow, and red winged blackbird. Black Tern Bog is owned by the DNR and was designated a State Natural Area in 1967.