Eagle Lake vs Mason Lake
Water quality, depth, fish species, and recreation comparison.
Eagle Lake has a higher water quality grade (A, Excellent) than Mason Lake (C, Fair). Both are in Otter Tail County, Minnesota.
Eagle Lake and Mason 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 meaningfully apart: Eagle Lake grades a A while Mason Lake grades a C. That two-letter spread reflects real underlying differences — different watershed inputs, different depth profiles, or different monitoring rigor.
For a recreational visitor, the wider grade gap is decisive — Eagle Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?
Eagle Lake
Crystal clear, you can see 22.6 ft down.
Mason Lake
Very murky, less than 3 ft of visibility.
Side-by-Side Metrics
| Metric | Eagle Lake | Mason Lake |
|---|---|---|
| Overall Grade | A (Excellent) | C (Fair) |
| Water Clarity | 22.6 ft | 3 ft |
| Phosphorus | 5 µg/L | 21 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 46 ft | 108 ft |
| Surface Area | 907.4 acres | 5.6K acres |
| Public Access | Yes | Yes |
| Fish Species | 10 | 17 |
| Trophic State | oligotrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Eagle Lake wins on overall water quality with a Grade A versus Mason Lake's Grade C. Water clarity: 22.6 ft vs 3 ft. For more fish-species variety, Mason Lake edges ahead with 17 documented species.