Brown County Lake Quality
Wisconsin, 3 lakes, average grade B (Good)
Brown 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. With an average grade of B, Brown County sits comfortably above the Wisconsin 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 Lily Lake (A); the most-stressed is Osnuhsa Lake (B).
Quick Answers for Brown County
Planning a trip? Check special fishing regulations for Lily Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
DNR Reports (4)
Wisconsin DNR Fisheries Survey resources for lakes in Brown County. browse all reports →
- 2021Status of Great Lakes Musky in Green Bay, 2021Musky Survey · WI DNR · 2021 (PDF)
- 2021Status of walleye in Southern Green Bay, 2021Walleye Survey · WI DNR · 2021 (PDF)
- 2018Green Bay walleye tagging survey, 2018Walleye Survey · WI DNR · 2018 (PDF)
- 2015Green Bay walleye tagging survey, 2015Walleye Survey · WI DNR · 2015 (PDF)
All Lakes in Brown County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Lily Lake | A | 33.1 ft | 19 ft | - |
| 2 | Quarry Lake | B | 26.2 ft | - | 29.5 µg/L |
| 3 | Osnuhsa Lake | B | 18.4 ft | - | 39.5 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.