Border Lakes, also known as the Catherine Wolter Wilderness Area, features a natural mosaic of forest habitats interspersed with 15 undeveloped lakes and large ponds. Of significance are the lakes, both named and unnamed, which all have unaltered shorelines, an increasingly uncommon condition in northern Wisconsin. In addition, the lakes have seen relatively little human activity over the last 60 years, allowing the biological structure of the lake communities to develop naturally. This has resulted in an unparalleled, representative group of aquatic ecosystems that are both functionally intact and remarkably similar within this ecoregion. Perhaps most remarkable is the fact that no non-native plant or animal species have yet been found in any of the lakes. The pristine quality of the lakes along with their unique biological attributes make them highly valuable as benchmarks for comparative research between managed and unmanaged lakes. As such, fishing is prohibited on some lakes as part of a long-term research project. Although logging has occurred throughout the site, the area still retains contiguous forest cover. Vegetation is varied and ranges from patches of very young aspen to near-mature stands of sugar maple, yellow birch, and hemlock. Low, poorly drained soils support both open and forested wetland assemblages including open bog, white cedar swamp, black ash swamp, northern wet forest dominated by black spruce and tamarack, and alder thickets. Numerous birds are known to nest here including yellow-bellied sapsucker, great crested flycatcher, hermit thrush, ovenbird, and rose-breasted grosbeak. Border Lakes State Natural Area is owned by the Wisconsin Chapter of The Nature Conservancy and was designated a State Natural Area in 2004.