Nelson County Lake Quality
Wisconsin, 9 lakes, average grade D (Poor)
Nelson County has 9 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. The county-wide average grade is D — water quality issues are persistent across most of the monitored basins. 3 lakes fall into the F bracket outright.
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 Whitman Dam Lake (B); the most-stressed is Mchugh Slough Lake (F).
Quick Answers for Nelson County
Planning a trip? Check special fishing regulations for Whitman Dam Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Nelson County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Whitman Dam Lake | B | 12 ft | - | - |
| 2 | Mcville Dam Lake | C | 6.9 ft | - | - |
| 3 | West Stump Lake | D | 9.8 ft | - | - |
| 4 | East Stump Lake | D | 8.5 ft | - | - |
| 5 | Tolna Dam Lake | D | 4.9 ft | - | - |
| 6 | Lake Laretta | D | 3.8 ft | - | 266 µg/L |
| 7 | Western Stump Lake | F | 4.3 ft | - | 154.5 µg/L |
| 8 | Eastern Stump Lake | F | 4.7 ft | - | 142 µg/L |
| 9 | Mchugh Slough Lake | F | 1.6 ft | - | 388.5 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.