Neda Mine, an abandoned iron mine located near the Village of Neda, Dodge County WI, is the site of the largest bat hibernaculum in the Midwest. The property was acquired by the University of Wisconsin-Milwaukee in 1976; at that time an estimated 75,000 bats were using the mine. More recent estimates suggest that the population has grown to 150,000 - 200,000 bats. The majority of these are little brown bats (Myotis lucifugus), but northern long-eared bats (Myotis septentrionalis), eastern pipistrelle bats (Pipistrellus subflavus) and big brown bats (Eptesicus fuscus) also occur.
In cooperation with the Wisconsin Department of Natural Resources, the Field Station is monitoring environmental conditions and bat activity patterns at the mine. The mine is also of geological interest; its cliffs provide an excellent exposure of the Niagara Dolomite and the only accessible exposure of the Neda Iron formation. Nearby, Neda Beechwoods lies on the escarpment and is a well-developed beech stand at the western boundary of beech. Neda Mine and Beechwoods are also Wisconsin State Natural Areas.