Carlton County Lake Quality
Minnesota, 33 lakes, average grade C (Fair)
Carlton County's 33 graded lakes fall in the moderate-density bracket for Minnesota. 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 average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
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 Lake (B); the most-stressed is Thomson Reservoir (F).
Quick Answers for Carlton County
Planning a trip? Check special fishing regulations for Big Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Minnesota regulations index.
DNR Reports (67)
Minnesota DNR LakeFinder resources for lakes in Carlton County. Showing 12 most recent — browse all reports →
- —Fisheries Lake Survey — Thomson ReservoirFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — TamarackFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — SandFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — ParkFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — MooseheadFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — MooseFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — BearFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — Lower (South) IslandFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — HayFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — Hanging HornFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — EddyFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — EchoFisheries Lake Survey · MN DNR LakeFinder
All Lakes in Carlton County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Big Lake | B | 9.1 ft | 25 ft | 12 µg/L |
| 2 | Third Lake | B | 8.5 ft | - | 13.5 µg/L |
| 3 | Pat Martin Lake | B | 6.6 ft | - | 15 µg/L |
| 4 | Moose Lake | B | 10 ft | 67 ft | - |
| 5 | Echo Lake | B | 11 ft | 47 ft | - |
| 6 | Cole Lake | B | 10 ft | 24 ft | - |
| 7 | Chub Lake | B | 13.3 ft | 28 ft | - |
| 8 | Lac Lake | B | 9.5 ft | - | 15.5 µg/L |
| 9 | Park Lake | B | 7 ft | 16 ft | 14 µg/L |
| 10 | Little Hanging Horn Lake | B | 11.5 ft | 31 ft | - |
| 11 | Kettle Lake | B | - | - | 29 µg/L |
| 12 | Sofie Lake | B | 4.9 ft | - | 20.5 µg/L |
| 13 | Wild Rice Lake | C | 3.2 ft | - | 21 µg/L |
| 14 | Spruce Lake | C | 2.3 ft | - | 19 µg/L |
| 15 | Hardwood Lake | C | 5.1 ft | - | 20 µg/L |
| 16 | Rice Portage Lake | C | 1.3 ft | - | 29.5 µg/L |
| 17 | Eagle Lake | C | 7 ft | 35 ft | 34 µg/L |
| 18 | Sand Lake | C | 5 ft | 27 ft | 29 µg/L |
| 19 | Perch Lake | C | 2.2 ft | - | 25 µg/L |
| 20 | Miller Lake | C | 1.8 ft | - | 32 µg/L |
| 21 | Deadfish Lake | C | 1.6 ft | - | 48.5 µg/L |
| 22 | Hay Lake | C | 6 ft | 14 ft | 24 µg/L |
| 23 | Jaskari Lake | C | 2.4 ft | - | 25 µg/L |
| 24 | Bang Lake | C | 2 ft | 9 ft | 43 µg/L |
| 25 | Island Lake | C | 5 ft | 22 ft | 45.5 µg/L |
| 26 | Cedar Lake | D | 2 ft | - | 40 µg/L |
| 27 | Eddy Lake | D | 3.5 ft | 37 ft | - |
| 28 | Tamarack Lake | D | 5 ft | 48 ft | - |
| 29 | Moosehead Lake | D | 4 ft | 18 ft | - |
| 30 | Second Lake | D | 1.2 ft | - | 78.5 µg/L |
| 31 | Hanging Horn Lake | D | 6 ft | 80 ft | - |
| 32 | Thomson Reservoir | F | 3 ft | 22 ft | - |
| 33 | Little Kettle Lake | F | 3.3 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.