Butternut Lake vs South Bay Lake
Water quality, depth, fish species, and recreation comparison.
Butternut Lake has a higher water quality grade (A, Excellent) than South Bay Lake (B, Good). Both are in Forest County, Wisconsin.
Both Butternut Lake and South Bay Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. These two are within a letter of each other on the rubric — Butternut Lake (A) versus South Bay Lake (B). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Butternut Lake
Crystal clear, you can see 19.5 ft down.
South Bay Lake
Good clarity, visible to about 12 ft.
Side-by-Side Metrics
| Metric | Butternut Lake | South Bay Lake |
|---|---|---|
| Overall Grade | A (Excellent) | B (Good) |
| Water Clarity | 19.5 ft | 12 ft |
| Phosphorus | 11.8 µg/L | No data |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 42 ft | 46 ft |
| Surface Area | 1.2K acres | 839 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | oligotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Butternut Lake wins on overall water quality with a Grade A versus South Bay Lake's Grade B. Water clarity: 19.5 ft vs 12 ft. For fishing diversity, Butternut Lake also leads with 0 species.