Nelson Lake vs Round Lake
Water quality, depth, fish species, and recreation comparison.
Round Lake reads lower on nutrients and algae than Nelson Lake. Both are in Sawyer County, Wisconsin.
Nelson Lake and Round Lake are both in Wisconsin — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The readings are close: Nelson Lake and Round Lake sit within a narrow band of each other on phosphorus, chlorophyll-a and clarity. The per-parameter table below shows where the small differences actually live.
With readings 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.
Nelson Lake
Murky, only visible to about 5 ft.
Round Lake
Crystal clear, you can see 21.1 ft down.
Side-by-Side Metrics
| Metric | Nelson Lake | Round Lake |
|---|---|---|
| Water Clarity | 5 ft | 21.1 ft Better |
| Phosphorus | 22.8 µg/L | 14 µg/L Better |
| Chlorophyll-a (Algae) | No data | 0.9 µg/L |
| Maximum Depth | - | 74 ft |
| Surface Area | 2,503 acres | 3,294 acres |
| Public Access | Yes | Yes |
| Fish Species | 0 | 6 Better |
| Trophic State | eutrophic | oligotrophic |
A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.
Swap a lake
Compare Nelson Lake or Round Lake against a different lake.
Verdict
Round Lake reads lower on nutrients and algae than Nelson Lake. Water clarity: 21.1 ft vs 5 ft. For fishing diversity, Round Lake also leads with 6 species.
Source: EPA National Aquatic Resource Surveys, 2026.