C
Cook County Lake Quality
Minnesota, 128 lakes, average grade C (Fair)
Cook County has 128 graded lakes, enough that within-county variation matters as much as the county average. Some are deep glacial basins, others are shallow agricultural-watershed waters, and the grade distribution reflects that mix. Cook 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.
Many of the county's lakes are deep glacial basins — over 50 feet at their deepest point — which gives them thermal stratification and a buffer against summer warming. Clearwater Lake (grade A) is the cleanest in the county.
Reviewed by LakeQuality Editorial Team · Updated
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Quick Answers for Cook County
Planning a trip? Check special fishing regulations for Clearwater Lake, and the best times to fish — or browse the full Minnesota regulations index.
DNR Reports (160)
Minnesota DNR LakeFinder resources for lakes in Cook County. Showing 12 most recent — browse all reports →
- —Fisheries Lake Survey — West TwinFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — West PikeFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — MountainFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — WardFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — Two IslandFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — TroutFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — TomFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — CrookedFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — TaitFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — StarFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — SouthFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — GullFisheries Lake Survey · MN DNR LakeFinder
All Lakes in Cook County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Clearwater Lake | A | 30 ft | 65 ft | 4 µg/L |
| 2 | Birch Lake | A | 18 ft | 69 ft | 8 µg/L |
| 3 | Round Lake | A | 16.5 ft | 45 ft | 8.5 µg/L |
| 4 | Pike Lake | A | 17.8 ft | 45 ft | 6 µg/L |
| 5 | Trout Lake | A | 19 ft | 77 ft | 9 µg/L |
| 6 | Gull Lake | A | 16.4 ft | - | 9 µg/L |
| 7 | Hungry Jack Lake | A | 18 ft | 71 ft | 7 µg/L |
| 8 | Pine Lake | A | 18 ft | 113 ft | - |
| 9 | Leo Lake | A | 15 ft | 28 ft | - |
| 10 | Duncan Lake | A | 22 ft | 130 ft | - |
| 11 | Lone Lake | A | 21 ft | - | - |
| 12 | Mayhew Lake | A | 20.6 ft | 84 ft | 5 µg/L |
| 13 | Loon Lake | A | 18 ft | 202 ft | 5 µg/L |
| 14 | Gunflint Lake | A | 20 ft | 200 ft | - |
| 15 | Kemo Lake | A | 17 ft | 65 ft | - |
| 16 | Flour Lake | A | 18.5 ft | 75 ft | 7 µg/L |
| 17 | Bearskin Lake | A | 21.3 ft | 78 ft | 6 µg/L |
| 18 | Peter Lake | A | 22.5 ft | 120 ft | - |
| 19 | Canoe Lake | A | 20.5 ft | 40 ft | - |
| 20 | Mcfarland Lake | A | 17 ft | 8 ft | 9 µg/L |
| 21 | Little Gunflint Lake | A | 16.2 ft | 200 ft | 7 µg/L |
| 22 | Rog Lake | A | 26.2 ft | 40 ft | - |
| 23 | Superior Lake | A | 15.1 ft | - | 4 µg/L |
| 24 | West Pike Lake | A | 19 ft | 120 ft | - |
| 25 | Taylor Lake Deep | A | 10.6 ft | - | 13 µg/L |
| 26 | Trout Lake Deep | A | 10.7 ft | - | 9.7 µg/L |
| 27 | Poplar Lake | A | 10.2 ft | 30 ft | 10 µg/L |
| 28 | Sea Gull Lake | A | 14.5 ft | 40 ft | 7 µg/L |
| 29 | Two Island Lake | A | 10.5 ft | 27 ft | 14 µg/L |
| 30 | Saganaga Lake | A | 12 ft | - | 7 µg/L |
| 31 | Greenwood Lake | A | 14.8 ft | 112 ft | 8 µg/L |
| 32 | Gogebic Lake | A | 13.8 ft | 61 ft | 5 µg/L |
| 33 | Alder Lake | A | 13.8 ft | 72 ft | 8 µg/L |
| 34 | West Twin Lake | B | 9.8 ft | 37 ft | 9 µg/L |
| 35 | Portage Lake | B | 8.5 ft | 55 ft | 9.5 µg/L |
| 36 | Caribou Lake | B | 7 ft | 6 ft | 15 µg/L |
| 37 | Devil Track Lake | B | 7 ft | 50 ft | 12.5 µg/L |
| 38 | Esther Lake | B | 10 ft | 35 ft | - |
| 39 | Red Rock Lake | B | 12.7 ft | 64 ft | - |
| 40 | Deer Yard Lake | B | 7.5 ft | 20 ft | 15 µg/L |
| 41 | East Bearskin Lake | B | 14 ft | 66 ft | - |
| 42 | Owl Lake | B | 13 ft | 70 ft | - |
| 43 | Rose Lake | B | 14.5 ft | 130 ft | - |
| 44 | Tom Lake | B | 9 ft | 35 ft | 8 µg/L |
| 45 | Tait Lake | B | 7.1 ft | 15 ft | 12.5 µg/L |
| 46 | Brule Lake | B | 10 ft | 78 ft | - |
| 47 | Jasper Lake | B | 12 ft | 125 ft | - |
| 48 | Ball Club Lake | B | 9.1 ft | 25 ft | 16.5 µg/L |
| 49 | Chester Lake | B | 11.9 ft | 35 ft | - |
| 50 | Alpine Lake | B | 12 ft | 65 ft | - |
| 51 | Clara Lake | B | 7.6 ft | 15 ft | 15 µg/L |
| 52 | Mesaba Lake | B | 10 ft | 65 ft | - |
| 53 | Alton Lake | B | 13.5 ft | 72 ft | - |
| 54 | Beth Lake | B | 11.1 ft | 22 ft | - |
| 55 | Dick Lake | B | 7.7 ft | 12 ft | 10 µg/L |
| 56 | Tarry Lake | B | 13 ft | 66 ft | - |
| 57 | Gabimichigami Lake | B | 14 ft | 209 ft | - |
| 58 | East Pike Lake | B | 12.2 ft | 40 ft | - |
| 59 | Chevans Lake Deep | B | 1.9 ft | - | 17.5 µg/L |
| 60 | Little Lake Deep | B | -324.8 ft | - | 14 µg/L |
| 61 | North Lake Deep | B | -324.8 ft | - | 7.7 µg/L |
| 62 | Rice Lake | B | 5.7 ft | 10 ft | 17 µg/L |
| 63 | East Twin Lake | B | 6.2 ft | 19 ft | 17 µg/L |
| 64 | Elbow Lake | B | 3.7 ft | 9 ft | 19 µg/L |
| 65 | Ward Lake | B | 5.6 ft | 13 ft | 16.5 µg/L |
| 66 | Ella Lake | B | 6 ft | - | 4 µg/L |
| 67 | Missouri Lake | B | 4.1 ft | 4 ft | 11 µg/L |
| 68 | Turtle Lake Deep | C | -324.8 ft | - | 22 µg/L |
| 69 | Teal Lake Deep | C | 3.3 ft | - | 15.5 µg/L |
| 70 | Horseshoe Lake | C | 7 ft | 26 ft | - |
| 71 | Caribou Lake | C | 8 ft | 26 ft | - |
| 72 | Lizz Lake | C | 9 ft | 30 ft | - |
| 73 | Copper Lake | C | 7 ft | 52 ft | - |
| 74 | Little Saganaga Lake | C | 9.3 ft | 150 ft | - |
| 75 | Gust Lake | C | 7 ft | 6 ft | - |
| 76 | Mora Lake | C | 8.5 ft | 40 ft | - |
| 77 | Davis Lake | C | 8.9 ft | 64 ft | - |
| 78 | Phoebe Lake | C | 7.5 ft | 25 ft | - |
| 79 | Loon Lake Deep | C | -324.8 ft | - | 23 µg/L |
| 80 | Karl Lake | C | 8 ft | 70 ft | - |
| 81 | South Lake | C | 8 ft | 140 ft | - |
| 82 | Dyers Lake | C | 4.9 ft | 23 ft | 21.5 µg/L |
| 83 | Cross Bay Lake | C | 7 ft | - | - |
| 84 | Sawbill Lake | C | 6.8 ft | 45 ft | - |
| 85 | Swamp Lake Deep | C | 1.7 ft | - | 27 µg/L |
| 86 | Rove Lake | C | 9 ft | 130 ft | - |
| 87 | Watap Lake | C | 9 ft | 210 ft | - |
| 88 | Long Island Lake | C | 8 ft | 85 ft | - |
| 89 | Mt Maud Lake | C | 3.4 ft | - | 34 µg/L |
| 90 | Helmer_nelson Pond Deep | C | 2.5 ft | - | 60 µg/L |
| 91 | Cuffs Lake Deep | C | -324.8 ft | - | 31 µg/L |
| 92 | Dutchman Lake Deep | D | 2.3 ft | - | 31 µg/L |
| 93 | Ada Lake | D | 5.5 ft | 13 ft | - |
| 94 | Star Lake | D | 4.9 ft | 13 ft | - |
| 95 | Homer Lake | D | 6 ft | 22 ft | - |
| 96 | Onagon Lake | D | 6 ft | 15 ft | - |
| 97 | Holly Lake | D | 4.9 ft | 6 ft | - |
| 98 | Hub Lake | D | 4.5 ft | - | - |
| 99 | Mt Maud Lake Inlet | D | 3.4 ft | - | - |
| 100 | Cuffs Lake Landing | D | 4.9 ft | - | - |
| 101 | Lower George Lake | D | 3.5 ft | - | - |
| 102 | Center Lakedeep | D | 1.4 ft | - | 53 µg/L |
| 103 | Chevans Lake Y | F | 1.9 ft | - | - |
| 104 | Mt Maud Lake Mid Basin | F | 2.5 ft | - | - |
| 105 | Swede Lake Deep | F | -324.8 ft | - | - |
| 106 | Mt Maud Lake Beaver Dam | F | 2.9 ft | - | - |
| 107 | Center Lakelanding | F | -161.7 ft | - | - |
| 108 | Helmer_nelson Pond Middle | F | 2.5 ft | - | - |
| 109 | Dutchman Lakelanding | F | 2.3 ft | - | - |
| 110 | Chaser Lake | F | 1 ft | 65 ft | - |
| 111 | Helmer_nelson Pond Inlet | F | 2.3 ft | - | - |
| 112 | Mt Maud Lake W_edge_basin | F | 2.5 ft | - | - |
| 113 | Helmer_nelson Pond East End Beaver House | F | 2.5 ft | - | - |
| 114 | Turtle Lake Inlet | F | -324.8 ft | - | - |
| 115 | Swede Lake Outlet | F | -324.8 ft | - | - |
| 116 | Swede Lake Inlet | F | -324.8 ft | - | - |
| 117 | Turtle Lake East End | F | -324.8 ft | - | - |
| 118 | Little Lake Inlet | F | -324.8 ft | - | - |
| 119 | Little Lake Landing | F | -324.8 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.