Cannon Lake vs Roberds Lake
Water quality, depth, fish species, and recreation comparison.
Cannon Lake and Roberds Lake both received the same overall water quality grade of F (Algae-prone). Both are in Rice County, Minnesota.
Both Cannon Lake and Roberds 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. These two are within a letter of each other on the rubric — Cannon Lake (F) versus Roberds Lake (F). 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.
Cannon Lake
Murky, only visible to about 4.1 ft.
Roberds Lake
Very murky, less than 2.5 ft of visibility.
Side-by-Side Metrics
| Metric | Cannon Lake | Roberds Lake |
|---|---|---|
| Overall Grade | F (Algae-prone) | F (Algae-prone) |
| Water Clarity | 4.1 ft Better | 2.5 ft |
| Phosphorus | 244 µg/L Better | 300 µg/L |
| Chlorophyll-a (Algae) | 46.5 µg/L Better | 86.7 µg/L |
| Maximum Depth | 15 ft | 43 ft Better |
| Surface Area | 1,593 acres | 632 acres |
| Public Access | Yes | Yes |
| Fish Species | 17 | 18 Better |
| Trophic State | eutrophic | hypereutrophic |
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 Cannon Lake or Roberds Lake against a different lake.
Verdict
Both lakes earn the same Grade F. The tiebreakers come down to clarity (Cannon Lake: 4.1 ft, Roberds Lake: 2.5 ft) and what you want from the lake. Cannon Lake has fewer fish species than Roberds Lake.
Source: EPA National Aquatic Resource Surveys, 2026.