Lenawee County Lake Quality
Wisconsin, 8 lakes, average grade B (Good)
Lenawee County has 8 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. With an average grade of B, Lenawee 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 Sand Lake Central Basin; Cambridge Township (A); the most-stressed is Posey Lake (D).
Quick Answers for Lenawee County
Planning a trip? Check special fishing regulations for Sand Lake Central Basin; Cambridge Township, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Lenawee County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Sand Lake Central Basin; Cambridge Township | A | 13.5 ft | - | - |
| 2 | Devils Lake Central Basin North | A | 10.8 ft | - | - |
| 3 | Round Lake Central Basin | A | 12 ft | - | - |
| 4 | Sand Lake | B | 13.3 ft | - | - |
| 5 | Devils Lake | B | 10.8 ft | - | - |
| 6 | Round Lake | B | 12.5 ft | - | - |
| 7 | Posey Lake Central Basin; Hudson Township | C | 5 ft | - | - |
| 8 | Posey Lake | D | 4.5 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.