Hillsdale County Lake Quality
Michigan, 5 lakes, average grade B (Good)
Only 5 lakes in Hillsdale County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. With an average grade of B, Hillsdale County sits comfortably above the Michigan median.
The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Crystal Lake (A); the most-stressed is Lake Diane (D).
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Quick Answers for Hillsdale County
Planning a trip? Check special fishing regulations for Crystal Lake, whether the fish are safe to eat, and the best times to fish — or check the official Michigan fishing regulations.
Fishing in Hillsdale County
All Lakes in Hillsdale County
5 lakes · 2 graded, 3 not rated2 graded lakes · 3 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | ACrystal LakeHillsdale | A | 9.5 ft | 11 µg/L | 4 µg/L | No recent samples | Not recorded |
| 2 | DLake DianeHillsdale | D | 2.5 ft | 51 µg/L | 20 µg/L | No recent samples | ✓ Public |
| NRFawn LakeHillsdale | NR | 4.5 ft | 38 µg/L | No recent samples | No recent samples | Not recorded | |
| NRPaw Paw LakeHillsdale | NR | 8 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRPerch LakeHillsdale | NR | 3.3 ft | 15 µg/L | No recent samples | No recent samples | ✓ Public |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
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Other Counties in Michigan
See how Hillsdale County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 49 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.