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LakeQuality
C

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 Horseshoe Lake (A); the most-stressed is Francis Lake (F).

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DNR Reports (40)

Minnesota DNR LakeFinder resources for lakes in Isanti County. browse all reports →

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

All Lakes in Isanti County

19 lakes · 17 graded, 2 not rated17 graded lakes · 2 not rated, hidden

#LakeGradeClarityPhosphorusAlgaeTrophicMax DepthAccess
1AHorseshoe LakeIsantiA3.5 ft13 µg/L2.7 µg/LNo recent samplesNo recent samplesCarry-in
2ASpectacle LakeIsantiA13.8 ft11 µg/L2.2 µg/LNo recent samples51.5 ft✓ Public
3AUpper Birch LakeIsantiA10.8 ft9.5 µg/L2.3 µg/LNo recent samplesNo recent samplesCarry-in
4ALower Birch LakeIsantiA7.4 ft19 µg/L3.6 µg/LNo recent samplesNo recent samplesCarry-in
5AHoffman LakeIsantiA3.7 ft15 µg/L3.6 µg/LNo recent samplesNo recent samplesCarry-in
6AHorseleg LakeIsantiA3.6 ft17 µg/L3 µg/LNo recent samplesNo recent samplesCarry-in
7CSkogman LakeIsantiC5.4 ft31 µg/L13.4 µg/LNo recent samples36 ft✓ Public
8CFannie LakeIsantiC6.9 ft35 µg/L9.3 µg/LNo recent samples33 ft✓ Public
9DTwin LakeIsantiD2.5 ft78 µg/L16 µg/LNo recent samplesNo recent samplesCarry-in
10DElms LakeIsantiD6.5 ft51.5 µg/L8.9 µg/LNo recent samples26 ftCarry-in
11DBlue LakeIsantiD8.9 ft44 µg/L21.4 µg/LNo recent samples31 ft✓ Public
12DGreen LakeIsantiD4.7 ft48 µg/L16.4 µg/LNo recent samples28 ft✓ Public
13DLory LakeIsantiD6 ft43 µg/L10.2 µg/LNo recent samples21 ft✓ Public
14DLittle Stanchfield LakeIsantiD3.5 ft122 µg/L25.4 µg/LNo recent samples12 ft✓ Public
15FFrancis LakeIsantiF2 ft159 µg/L56.1 µg/LNo recent samples7 ft✓ Public
16FSouth Stanchfield LakeIsantiF2.5 ft119 µg/L32 µg/LNo recent samples17 ft✓ Public
17FNorth Stanchfield LakeIsantiF2.8 ft190.5 µg/L54.7 µg/LNo recent samples11 ftCarry-in
NRFlorence LakeIsantiNR8.9 ftNo recent samplesNo recent samplesNo recent samples26 ft✓ Public
NRKrans LakeIsantiNR1.5 ftNo recent samplesNo recent samplesNo recent samples31 ftCarry-in

NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

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See how Isanti County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.

Source: EPA National Aquatic Resource Surveys, 2026.