Big Mcdonald Lake vs Sybil Lake
Water quality, depth, fish species, and recreation comparison.
Big Mcdonald Lake and Sybil Lake read the same on nutrients and algae. Both are in Otter Tail County, Minnesota.
Both Big Mcdonald Lake and Sybil Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any differences in the readings here are about the lakes themselves, not the agencies sampling them. These two sit close on the readings, Big Mcdonald Lake versus Sybil Lake. The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
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.
Big Mcdonald Lake
Crystal clear, you can see 17.4 ft down.
Sybil Lake
Crystal clear, you can see 20 ft down.
Side-by-Side Metrics
| Metric | Big Mcdonald Lake | Sybil Lake |
|---|---|---|
| Water Clarity | 17.4 ft | 20 ft Better |
| Phosphorus | 12 µg/L | 9 µg/L Better |
| Chlorophyll-a (Algae) | 3.2 µg/L | 2.4 µg/L Better |
| Maximum Depth | 46 ft | 74 ft Better |
| Surface Area | 992 acres | 683 acres |
| Public Access | Yes | Yes |
| Fish Species | 15 | 16 Better |
| Trophic State | oligotrophic | oligotrophic |
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 Big Mcdonald Lake or Sybil Lake against a different lake.
Verdict
Both lakes earn the same Grade A. The tiebreakers come down to clarity (Big Mcdonald Lake: 17.4 ft, Sybil Lake: 20 ft) and what you want from the lake. Big Mcdonald Lake has fewer fish species than Sybil Lake.
Source: EPA National Aquatic Resource Surveys, 2026.