Brown County Lake Quality
Wisconsin, 3 lakes, average grade C (Fair)
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. Brown 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 Quarry Lake (C); the most-stressed is Osnuhsa Lake (C).
Quick Answers for Brown County
Planning a trip? Check special fishing regulations for Quarry 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 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 | Quarry Lake | C | 8 ft | - | 29.5 µg/L |
| 2 | Lily Lake | C | 9.6 ft | 19 ft | - |
| 3 | Osnuhsa Lake | C | 5.6 ft | - | 39.5 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.