Lower Hay Lake vs Upper Hay Lake
Water quality, depth, fish species, and recreation comparison.
Lower Hay Lake and Upper Hay Lake both received the same overall water quality grade of A (Excellent). Both are in Crow Wing County, Minnesota.
Both Lower Hay Lake and Upper Hay 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: Lower Hay Lake (A) and Upper Hay 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.
Lower Hay Lake
Crystal clear, you can see 18.5 ft down.
Upper Hay Lake
Good clarity, visible to about 10.9 ft.
Side-by-Side Metrics
| Metric | Lower Hay Lake | Upper Hay Lake |
|---|---|---|
| Overall Grade | A (Excellent) | A (Excellent) |
| Water Clarity | 18.5 ft | 10.9 ft |
| Phosphorus | 13 µg/L | 20 µg/L |
| Chlorophyll-a (Algae) | 2.7 µg/L | 4.8 µg/L |
| Maximum Depth | 100 ft | 42 ft |
| Surface Area | 700 acres | 596 acres |
| Public Access | Yes | Yes |
| Fish Species | 21 | 13 |
| Trophic State | oligotrophic | 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 (Lower Hay Lake: 18.5 ft, Upper Hay Lake: 10.9 ft) and what you want from the lake. Lower Hay Lake supports more documented fish species.
Source: EPA National Aquatic Resource Surveys, 2026.