Wisconsin Slough features a unique wetland complex with a hard water spring pond surrounded by diverse sedge meadow and conifer swamp. The 5.6-acre spring pond has alkaline shallow water and a deep silt bottom. The springs originate near the base of a steep northeast-facing morainal slope and flow via a short outlet stream directly to the Brule River. The dominant aquatic plant in the spring pool is stonewort, a green Chara alga. Other species include sago pondweed and white water crowfoot. A narrow zone of emergent aquatic vegetation borders the pond with arrowhead, softstem bulrush, cattail, and sweetgale. A small open wet meadow dominated by tussock sedge occurs on the pond's east end. Also present are spike rushes, blue-joint grass, marsh fern, blue flag, spotted joe-pye weed, and lesser purple fringed orchid. Swamp conifers and alder flank the outlet stream and sedge meadow composed mainly of tamarack, black spruce, and white cedar. The moderately steep slopes east of the outlet stream are forested with jack pine, red pine, and white pine while trembling aspen and paper birch dominate the slopes west of the pond. Bird species include great blue heron, belted kingfisher, sharp-shinned hawk, raven, and golden-crowned kinglet. Wisconsin Slough is owned by the USDA Forest Service and was designated a State Natural Area in 1996.