Calhoun Lake vs Koronis Lake
Water quality, depth, fish species, and recreation comparison.
Calhoun Lake and Koronis Lake both received the same overall water quality grade of C (Fair). Both are in Minnesota.
Both Calhoun Lake and Koronis Lake sit in Minnesota. 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. The grades are close: Calhoun Lake (C) and Koronis Lake (C) are within one letter of each other on our A–F scale. The per-parameter sub-grades below will show where the small differences actually live.
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.
Calhoun Lake
Moderate clarity, visible to about 6.9 ft.
Koronis Lake
Murky, only visible to about 6 ft.
Side-by-Side Metrics
| Metric | Calhoun Lake | Koronis Lake |
|---|---|---|
| Overall Grade | C (Fair) | C (Fair) |
| Water Clarity | 6.9 ft Better | 6 ft |
| Phosphorus | 24 µg/L Better | 27 µg/L |
| Chlorophyll-a (Algae) | 8.8 µg/L Better | 13.8 µg/L |
| Maximum Depth | 13 ft | 132 ft Better |
| Surface Area | 647 acres | 2,968 acres |
| Public Access | Yes | Yes |
| Fish Species | 15 | 22 Better |
| Trophic State | eutrophic | 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 Calhoun Lake or Koronis Lake against a different lake.
Verdict
Both lakes earn the same Grade C. The tiebreakers come down to clarity (Calhoun Lake: 6.9 ft, Koronis Lake: 6 ft) and what you want from the lake. Calhoun Lake has fewer fish species than Koronis Lake.
Source: EPA National Aquatic Resource Surveys, 2026.