Isanti County Lake Quality
Minnesota, 19 lakes, average grade C (Fair)
There are 19 graded lakes in Isanti County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. Isanti 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.
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 Lower Birch Lake (A); the most-stressed is Krans Lake (F).
Quick Answers for Isanti County
Planning a trip? Check special fishing regulations for Lower Birch Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Minnesota regulations index.
DNR Reports (41)
Minnesota DNR LakeFinder resources for lakes in Isanti County. Showing 12 most recent — browse all reports →
- —Fisheries Lake Survey — SpectacleFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — South StanchfieldFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — SkogmanFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — North StanchfieldFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — LoryFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — Little StanchfieldFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — KransFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — GreenFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — FrancisFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — FlorenceFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — FannieFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — ElmsFisheries Lake Survey · MN DNR LakeFinder
All Lakes in Isanti County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Lower Birch Lake | A | 10.8 ft | - | 15 µg/L |
| 2 | Spectacle Lake | A | 13.8 ft | 51.5 ft | 11 µg/L |
| 3 | Upper Birch Lake | A | 10.8 ft | - | 9.5 µg/L |
| 4 | Horseshoe Lake | B | 3.6 ft | - | 12 µg/L |
| 5 | Hoffman Lake | B | 4.1 ft | - | 15 µg/L |
| 6 | Horseleg Lake | B | 3.7 ft | - | 17 µg/L |
| 7 | Fannie Lake | C | 7 ft | 33 ft | 37 µg/L |
| 8 | Elms Lake | C | 6.9 ft | 26 ft | 53 µg/L |
| 9 | Blue Lake | C | 8.9 ft | 31 ft | 47 µg/L |
| 10 | Florence Lake | C | 9 ft | 26 ft | - |
| 11 | Green Lake | C | 5.1 ft | 28 ft | 44 µg/L |
| 12 | Skogman Lake | C | 5.4 ft | 36 ft | 31 µg/L |
| 13 | Lory Lake | C | 6 ft | 21 ft | 41 µg/L |
| 14 | Francis Lake | D | 2 ft | 7 ft | 62 µg/L |
| 15 | Twin Lake | D | 2.6 ft | - | 110 µg/L |
| 16 | Little Stanchfield Lake | D | 3.5 ft | 12 ft | 132 µg/L |
| 17 | Krans Lake | F | 1.6 ft | 31 ft | - |
| 18 | North Stanchfield Lake | F | 2.8 ft | 11 ft | 171 µg/L |
| 19 | South Stanchfield Lake | F | 2.5 ft | 17 ft | 119 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.