Keweenaw County Lake Quality
Wisconsin, 19 lakes, average grade B (Good)
There are 19 graded lakes in Keweenaw County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. With an average grade of B, Keweenaw County sits comfortably above the Michigan 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 Lake Gratiot (A); the most-stressed is Hidden Lake (C).
Quick Answers for Keweenaw County
Planning a trip? Check special fishing regulations for Lake Gratiot, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Keweenaw County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Lake Gratiot | A | 17.8 ft | - | - |
| 2 | Su10 Lake | A | 50.5 ft | - | - |
| 3 | Gratiot Lake | A | 19 ft | - | - |
| 4 | Su14 Lake | A | - | - | - |
| 5 | Su12 Lake | A | 27.9 ft | - | - |
| 6 | Su13 Lake | A | 34.9 ft | - | - |
| 7 | Lake Harvey | A | 10.5 ft | - | 11.6 µg/L |
| 8 | Sargent Lake | A | 10.4 ft | - | 17.3 µg/L |
| 9 | Siskiwit Lake | A | 19.3 ft | - | 24.5 µg/L |
| 10 | Lake Richie | B | 8.3 ft | - | 17.8 µg/L |
| 11 | Beaver Lake | B | 8 ft | - | 17.1 µg/L |
| 12 | Feldtmann Lake | B | 7.3 ft | - | 14.2 µg/L |
| 13 | Lake George | B | 8 ft | - | 9.9 µg/L |
| 14 | Lake Ahmik | B | 7 ft | - | 17 µg/L |
| 15 | Lake Whittlesey | B | 11.6 ft | - | 23.3 µg/L |
| 16 | Lake Desor | B | 7.8 ft | - | 22.7 µg/L |
| 17 | Chickenbone Lake | C | 6.1 ft | - | 28.2 µg/L |
| 18 | Epidote Lake | C | 7.2 ft | - | - |
| 19 | Hidden Lake | C | 2.5 ft | - | 27.5 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.