Black Tern Bog State Natural Area is a Wisconsin Department of Natural Resources-designated State Natural Area featuring 20 acres (8 ha) of quaking sphagnum bog surrounding two small seepage lakes situated in a pitted outwash plain. The bog is rich in plant species, such as sundews, pitcher plant, bogbean, and bog rosemary, as well as three species of bog orchids: swamp pink, grass pink, and rose pogonia. The state-endangered bog rush (Juncus stygius) also grows here. Birds known to nest here include black tern, American bittern, killdeer, and mallards.