Beltrami Lake vs Big Lake
Water quality, depth, fish species, and recreation comparison.
Beltrami Lake and Big Lake both received the same overall water quality grade of A (Excellent). Both are in Beltrami County, Minnesota.
Both Beltrami Lake and Big 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: Beltrami Lake (A) and Big Lake (A) are within one letter of each other on the LakeGrade rubric. 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.
Beltrami Lake
Good clarity, visible to about 11.2 ft.
Big Lake
Moderate clarity, visible to about 9.7 ft.
Side-by-Side Metrics
| Metric | Beltrami Lake | Big Lake |
|---|---|---|
| Overall Grade | A (Excellent) | A (Excellent) |
| Water Clarity | 11.2 ft | 9.7 ft |
| Phosphorus | 15 µg/L | 15 µg/L |
| Chlorophyll-a (Algae) | 4.3 µg/L | 4.8 µg/L |
| Maximum Depth | 50 ft | 35 ft |
| Surface Area | 726 acres | 3,598 acres |
| Public Access | Yes | Yes |
| Fish Species | 16 | 17 |
| Trophic State | mesotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Both lakes earn the same Grade A. The tiebreakers come down to clarity (Beltrami Lake: 11.2 ft, Big Lake: 9.7 ft) and what you want from the lake. Beltrami Lake has fewer fish species than Big Lake.
Source: EPA National Aquatic Resource Surveys, 2026.