Big Lake vs Medicine Lake
Water quality, depth, fish species, and recreation comparison.
Big Lake has a higher water quality grade (A, Excellent) than Medicine Lake (B, Good). Both are in Beltrami County, Minnesota.
Big Lake and Medicine 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 grades are close: Big Lake (A) and Medicine Lake (B) 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.
Big Lake
Moderate clarity, visible to about 9.7 ft.
Medicine Lake
Moderate clarity, visible to about 7.9 ft.
Side-by-Side Metrics
| Metric | Big Lake | Medicine Lake |
|---|---|---|
| Overall Grade | A (Excellent) | B (Good) |
| Water Clarity | 9.7 ft | 7.9 ft |
| Phosphorus | 15 µg/L | 23 µg/L |
| Chlorophyll-a (Algae) | 4.8 µg/L | 7.1 µg/L |
| Maximum Depth | 35 ft | 44 ft |
| Surface Area | 3,598 acres | 461 acres |
| Public Access | Yes | Yes |
| Fish Species | 17 | 12 |
| Trophic State | mesotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Big Lake wins on overall water quality with a Grade A versus Medicine Lake's Grade B. Water clarity: 9.7 ft vs 7.9 ft. For fishing diversity, Big Lake also leads with 17 species.
Source: EPA National Aquatic Resource Surveys, 2026.