Lafayette County Lake Quality
Wisconsin, 3 lakes, average grade C (Fair)
Lafayette County has 3 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. Lafayette County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
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 Hidden Valley Lake (C); the most-stressed is Yellowstone Lake (F).
Quick Answers for Lafayette County
Planning a trip? Check special fishing regulations for Hidden Valley Lake, and the best times to fish — or browse the full Wisconsin regulations index.
DNR Reports (4)
Wisconsin DNR Fisheries Survey resources for lakes in Lafayette County. browse all reports →
- 2023Yellowstone Lake rough fish removal assessment, 2023Fisheries Survey · WI DNR · 2023 (PDF)
- 2018Yellowstone Lake comprehensive survey 2018Comprehensive Survey · WI DNR · 2018 (PDF)
- 2016East Branch Pecatonica River catfish hoop net survey, 2016Fisheries Survey · WI DNR · 2016 (PDF)
- 2010Yellowstone Lake muskellunge 2010Musky Survey · WI DNR · 2010 (PDF)
All Lakes in Lafayette County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Hidden Valley Lake | C | 5 ft | 18 ft | 44.7 µg/L |
| 2 | Yellowstone Lake | F | 1.2 ft | 14 ft | 156 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.