Washburn County Lake Quality
Wisconsin, 47 lakes, average grade B (Good)
Washburn County's 47 graded lakes fall in the moderate-density bracket for Wisconsin. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.
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 Big Bass Lake (A); the most-stressed is Unnamed Lake (F).
Quick Answers for Washburn County
Planning a trip? Check special fishing regulations for Big Bass Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
DNR Reports (2)
Wisconsin DNR Fisheries Survey resources for lakes in Washburn County. browse all reports →
- 2023Minong Flowage comprehensive survey, 2023Comprehensive Survey · WI DNR · 2023 (PDF)
- 2023Stone Lake comprehensive survey, 2023Comprehensive Survey · WI DNR · 2023 (PDF)
All Lakes in Washburn County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Big Bass Lake | A | 17.9 ft | 27 ft | - |
| 2 | Bass Lake | A | 16 ft | 31 ft | 12.3 µg/L |
| 3 | Stone Lake | A | 23 ft | 49 ft | 10.8 µg/L |
| 4 | Loon Lake | A | - | 63 ft | 7 µg/L |
| 5 | Shell Lake | A | 16 ft | 36 ft | 15.2 µg/L |
| 6 | Spring Lake | A | - | 24 ft | 14.8 µg/L |
| 7 | Tozer Lake | A | 16 ft | 53 ft | 13.2 µg/L |
| 8 | Middle Kimball Lake | A | 16 ft | 77 ft | 13.1 µg/L |
| 9 | Big Bass Lake | A | - | 27 ft | 11.7 µg/L |
| 10 | Slim Lake | A | 15.7 ft | - | 13.6 µg/L |
| 11 | Trego Lake | A | - | 36 ft | 16.5 µg/L |
| 12 | Lower Mckenzie Lake | A | 11 ft | - | 18.8 µg/L |
| 13 | Bean Lake | A | 10 ft | 35 ft | 16.2 µg/L |
| 14 | Horseshoe Lake | A | 13 ft | 21 ft | 12.6 µg/L |
| 15 | Matthews Lake | A | 13.5 ft | 26 ft | 13.7 µg/L |
| 16 | Lake Nancy | A | 14 ft | 39 ft | 13.5 µg/L |
| 17 | South Twin Lake | A | 14 ft | 29 ft | 11 µg/L |
| 18 | Gilmore Lake | A | 10 ft | 36 ft | 16.3 µg/L |
| 19 | Big Mckenzie Lake | A | 10 ft | 71 ft | 17 µg/L |
| 20 | Balsam Lake | B | 8.8 ft | - | 19.3 µg/L |
| 21 | Silver Lake | B | 11 ft | 28 ft | - |
| 22 | Deep Lake | B | 7.5 ft | 25 ft | 16.5 µg/L |
| 23 | Bass Lake | B | 14 ft | 35 ft | - |
| 24 | Long Lake | B | 9.5 ft | - | 17.5 µg/L |
| 25 | Island Lake | B | 14.5 ft | 44 ft | - |
| 26 | North Twin Lake | B | 9 ft | - | 13.7 µg/L |
| 27 | Little Sand Lake | B | 12 ft | 21 ft | - |
| 28 | Mclain Lake | B | 9.5 ft | 30 ft | 14.2 µg/L |
| 29 | Upper Kimball Lake | B | 10 ft | 11 ft | 20.4 µg/L |
| 30 | Unnamed Lake | B | - | - | 28.4 µg/L |
| 31 | Dunn Lake | B | 14.2 ft | 39 ft | - |
| 32 | Yellow River Flowage Lake | B | 10 ft | 17 ft | 23.1 µg/L |
| 33 | Lower Kimball Lake | B | 6 ft | 6 ft | 18.5 µg/L |
| 34 | Spider Lake | C | 9.5 ft | - | - |
| 35 | Birch Lake | C | 5.5 ft | 73 ft | 27.6 µg/L |
| 36 | Potato Lake | C | 9.5 ft | 20 ft | 33.2 µg/L |
| 37 | Ripley Lake | C | 8.5 ft | 27 ft | - |
| 38 | Middle Twin Lake at | C | 7.5 ft | - | - |
| 39 | No Mans Lake | C | 9 ft | 23 ft | - |
| 40 | Gull Lake | C | 8.5 ft | 19 ft | - |
| 41 | Spooner Lake | C | 6.5 ft | - | 22.7 µg/L |
| 42 | Kekegama Lake | C | 5.2 ft | 24 ft | 26.4 µg/L |
| 43 | Minong Flowage Lake | C | 3.5 ft | 21 ft | 37.2 µg/L |
| 44 | Mud Lake | D | - | 13 ft | 70.7 µg/L |
| 45 | Unnamed Lake | D | 6.5 ft | 10 ft | - |
| 46 | Unnamed Lake | F | 3.3 ft | 3 ft | - |
Source: EPA National Aquatic Resource Surveys, 2026.