Nelson Lake is 3,072 acres of water, 31 miles of shoreline, 16 islands ( Big Island is included in the DNR Land Legacy sites) and a few floating bogs. Its water source comes from two named streams, the Totagatic River and Tagalder Creek, and at least four other specific drainage streams. The total watershed drainage area and lake cover about 34,800 acres (approximately 54 square miles).
It is home to at least three pair of nesting eagles, two osprey nests, four pair of nesting loons, and a nesting pair of Trumpeter Swans.
Nelson Lake has a large variety of fish including; walleye, largemouth bass, northern pike, crappie, bluegill, perch, and bullheads.