Extremely scenic and undeveloped, Day Lake is a 117-acre seepage lake with very sterile, exceptionally clear water. The lake's sandy bed is visible in 28 feet of water and supports an excellent example of "sterile rosette flora" - small, stiff-leaved plants that hug the bottom. These small plants are indicative of the very soft water conditions. The specialized flora includes water lobelia and quillwort. Other aquatic plants include dwarf water milfoil, seven-angle pipewort, small waterwort, and narrow-leaved bur-reed. Emergent vegetation consisting of sweet gale, leather-leaf, alder, and three-way sedge forms a zone along the lakeshore. The lake has a watershed of only 510 acres and 3.5 miles of gravelly upland shoreline. Bass and panfish comprise the fishery. Two primitive campsites on the lakeshore may be reserved. Day Lake is owned by the DNR and was designated a State Natural Area in 1983.