Cleanest Lakes in Minnesota & Wisconsin
The top 50 lakes ranked by overall water quality grade. Grades are based on water clarity (Secchi depth in feet), phosphorus levels, and chlorophyll-a (algae) concentration using Metropolitan Council standards.
| Rank | Lake | County | State | Grade | Clarity | Max Depth |
|---|---|---|---|---|---|---|
| 1 | East Fox Lake | Crow Wing | MN | A | 16.1 ft | 65 ft |
| 2 | Deep Portage Lake | Cass | MN | A | 15.4 ft | 105 ft |
| 3 | Little Wabana Lake | Itasca | MN | A | 23.8 ft | 57 ft |
| 4 | Clearwater Lake | Cook | MN | A | 30 ft | 65 ft |
| 5 | Clearwater Lake | Lake | MN | A | 18 ft | 46 ft |
| 6 | Lower Hay Lake | Crow Wing | MN | A | 19 ft | 100 ft |
| 7 | Latoka Lake | Douglas | MN | A | 19 ft | 108 ft |
| 8 | Bad Medicine Lake | Becker | MN | A | 25 ft | 84 ft |
| 9 | Big Sugar Bush Lake | Becker | MN | A | 17 ft | 42 ft |
| 10 | Pelican Lake | Otter Tail | MN | A | 16.1 ft | 55 ft |
| 11 | Fullers Lake: East Basin | Beltrami | MN | A | 49.2 ft | — |
| 12 | Birch Lake | Wright | MN | A | 15 ft | 52 ft |
| 13 | Birch Lake | Cook | MN | A | 18 ft | 69 ft |
| 14 | Birch Lake | Unknown | MN | A | 15 ft | 34 ft |
| 15 | Round Lake | Aitkin | MN | A | 15.3 ft | 59 ft |
| 16 | Round Lake | Cook | MN | A | 16.5 ft | 45 ft |
| 17 | Round Lake | Beltrami | MN | A | 59.1 ft | 38 ft |
| 18 | Pike Lake | Cook | MN | A | 17.8 ft | 45 ft |
| 19 | Pike Lake | St. Louis | MN | A | 18 ft | 60 ft |
| 20 | Whitefish Lake | Crow Wing | MN | A | 15.1 ft | 138 ft |
| 21 | Horseshoe Lake | Cass | MN | A | 21 ft | 51 ft |
| 22 | Long Lake | Clearwater | MN | A | 20 ft | 80 ft |
| 23 | Long Lake | Cass | MN | A | 21.8 ft | 115 ft |
| 24 | Long Lake | Beltrami | MN | A | 20 ft | 87 ft |
| 25 | Long Lake | Becker | MN | A | 20 ft | 61 ft |
| 26 | Long Lake | Cass | MN | A | 16.8 ft | 37 ft |
| 27 | Long Lake | Beltrami | MN | A | 45.9 ft | — |
| 28 | Long Lake | Itasca | MN | A | 16.7 ft | 72 ft |
| 29 | Long Lake | Itasca | MN | A | 16.9 ft | 85 ft |
| 30 | Dead Lake | Hubbard | MN | A | 16 ft | 34 ft |
| 31 | Unnamed Lake | Otter Tail | MN | A | 15.1 ft | 95 ft |
| 32 | Maple Lake | Itasca | MN | A | 15.3 ft | 39 ft |
| 33 | West Twin Lake | Crow Wing | MN | A | 19.8 ft | — |
| 34 | Sunshine Lake | St. Louis | MN | A | 20 ft | 37 ft |
| 35 | Shallow Lake | Itasca | MN | A | 16.4 ft | 85 ft |
| 36 | Trout Lake | Itasca | MN | A | 15.5 ft | 135 ft |
| 37 | Trout Lake | Itasca | MN | A | 18 ft | 157 ft |
| 38 | Trout Lake | Cook | MN | A | 19 ft | 77 ft |
| 39 | Chippewa Lake | Douglas | MN | A | 15.1 ft | 95 ft |
| 40 | Otter Lake | Otter Tail | MN | A | 18 ft | 64 ft |
| 41 | Eddy Lake | Lake | MN | A | 16.5 ft | 95 ft |
| 42 | Cowdry Lake | Douglas | MN | A | 17 ft | 52 ft |
| 43 | Ossawinnamakee Lake | Crow Wing | MN | A | 20 ft | 63 ft |
| 44 | Clear Lake | Crow Wing | MN | A | 18 ft | 63 ft |
| 45 | Clear Lake | Aitkin | MN | A | 16 ft | 24 ft |
| 46 | Clear Lake | Itasca | MN | A | 14.9 ft | 30 ft |
| 47 | Bear Lake | Lake | MN | A | 17.4 ft | 31 ft |
| 48 | Emerald Lake | Beltrami | MN | A | 31.2 ft | — |
| 49 | Blue Lake | Hubbard | MN | A | 17.4 ft | 84 ft |
| 50 | Blue Lake | Crow Wing | MN | A | 19 ft | 48 ft |