Lac Courte Oreilles Lake vs Nelson Lake
Water quality, depth, fish species, and recreation comparison.
Lac Courte Oreilles Lake reads lower on nutrients and algae than Nelson Lake. Both are in Sawyer County, Wisconsin.
Both Lac Courte Oreilles Lake and Nelson Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any differences in the readings here are about the lakes themselves, not the agencies sampling them. The readings are close: Lac Courte Oreilles Lake and Nelson 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.
Lac Courte Oreilles Lake
Good clarity, visible to about 12.2 ft.
Nelson Lake
Murky, only visible to about 5 ft.
Side-by-Side Metrics
| Metric | Lac Courte Oreilles Lake | Nelson Lake |
|---|---|---|
| Water Clarity | 12.2 ft Better | 5 ft |
| Phosphorus | 15 µg/L Better | 22.8 µg/L |
| Chlorophyll-a (Algae) | 1.7 µg/L | No data |
| Maximum Depth | 90 ft | - |
| Surface Area | 5,139 acres | 2,503 acres |
| Public Access | Yes | Yes |
| Fish Species | 6 Better | 0 |
| Trophic State | mesotrophic | eutrophic |
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 Lac Courte Oreilles Lake or Nelson Lake against a different lake.
Verdict
Lac Courte Oreilles Lake reads lower on nutrients and algae than Nelson Lake. Water clarity: 12.2 ft vs 5 ft. For fishing diversity, Lac Courte Oreilles Lake also leads with 6 species.
Source: EPA National Aquatic Resource Surveys, 2026.