Three Island Lake vs Turtle Lake
Water quality, depth, fish species, and recreation comparison.
Three Island Lake and Turtle Lake read the same on nutrients and algae. Both are in Beltrami County, Minnesota.
Three Island Lake and Turtle Lake are both in Minnesota — 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: Three Island Lake and Turtle 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.
Three Island Lake
Good clarity, visible to about 11.8 ft.
Turtle Lake
Good clarity, visible to about 10.2 ft.
Side-by-Side Metrics
| Metric | Three Island Lake | Turtle Lake |
|---|---|---|
| Water Clarity | 11.8 ft Better | 10.2 ft |
| Phosphorus | 17 µg/L | 15 µg/L Better |
| Chlorophyll-a (Algae) | 4.1 µg/L Better | 4.9 µg/L |
| Maximum Depth | 25 ft | 45 ft Better |
| Surface Area | 729 acres | 1,607 acres |
| Public Access | Yes | Yes |
| Fish Species | 17 Better | 16 |
| Trophic State | mesotrophic | mesotrophic |
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 Three Island Lake or Turtle Lake against a different lake.
Verdict
Both lakes earn the same Grade A. The tiebreakers come down to clarity (Three Island Lake: 11.8 ft, Turtle Lake: 10.2 ft) and what you want from the lake. Three Island Lake supports more documented fish species.
Source: EPA National Aquatic Resource Surveys, 2026.