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LakeQuality

Best Swimming Lakes in Minnesota

East Fox Lake (Crow Wing County) ranks #1 for swimming in Minnesota — grade A water with low algae and public access. Below: the top 25 lakes in Minnesotathat pass our swim-safety filter (grade A/B, chlorophyll-a below 10 µg/L).

RankLakeCountyGradeClarityAlgaePhosphorusArea
1East Fox LakeCrow WingA16.1 ft10 µg/L240.88 acres
2Deep Portage LakeCassA15.4 ft10 µg/L129.02 acres
3Little Wabana LakeItascaA23.8 ft6.5 µg/L115.73 acres
4Clearwater LakeCookA30 ft4 µg/L461.73 acres
5Lower Hay LakeCrow WingA19 ft13 µg/L700.21 acres
6Latoka LakeDouglasA19 ft11 µg/L766.63 acres
7Bad Medicine LakeBeckerA25 ft6 µg/L803.03 acres
8Big Sugar Bush LakeBeckerA17 ft10 µg/L521.51 acres
9Pelican LakeOtter TailA16.1 ft15 µg/L4.0K acres
10Fullers Lake: East BasinBeltramiA49.2 ft9.5 µg/L-
11Birch LakeWrightA15 ft17 µg/L99.82 acres
12Birch LakeCookA18 ft8 µg/L236.31 acres
13Round LakeCookA16.5 ft8.5 µg/L154.48 acres
14Round LakeBeltramiA59.1 ft7 µg/L181.06 acres
15Pike LakeCookA17.8 ft6 µg/L814.43 acres
16Whitefish LakeCrow WingA15.1 ft14 µg/L7.7K acres
17Long LakeClearwaterA20 ft7 µg/L158.86 acres
18Long LakeCassA21.8 ft9 µg/L1.0K acres
19Long LakeBeltramiA20 ft7 µg/L411.95 acres
20Long LakeBeckerA20 ft8 µg/L414.51 acres
21Long LakeBeltramiA45.9 ft8 µg/L-
22Long LakeItascaA16.7 ft8 µg/L155.28 acres
23Long LakeItascaA16.9 ft10 µg/L134.49 acres
24Dead LakeHubbardA16 ft10 µg/L130.64 acres
25Unnamed LakeOtter TailA15.1 ft9 µg/L1.4K acres

Frequently Asked Questions

What is the best lake to swim in Minnesota?

East Fox Lake in Crow Wing County ranks #1 for swimming-safety in our 2026 Minnesota dataset, combining grade-A water clarity with low algae and public access. The full top 25 above ranks the swim-safest lakes statewide.

How do you know if a lake is safe to swim in Minnesota?

Three signals: (1) water clarity — Secchi depth above 6 feet is a strong sign of low suspended sediment and pathogens; (2) chlorophyll-a below 10 µg/L means low risk of harmful algae bloom; (3) a current grade of A or B from year-round sampling. Minnesota DNR and county health departments post seasonal advisories — always check before you swim, especially in late summer when blue-green algae bloom risk peaks.

Are lakes in Minnesota safe to swim in?

Most monitored Minnesota lakes are safe to swim in under normal conditions, but water quality varies widely. The lakes ranked above are filtered to grade A and B with chlorophyll-a below 10 µg/L — meaning they consistently test cleaner and have lower algae bloom risk than the state average. Always check posted advisories before swimming and avoid water after heavy rain (bacterial contamination spikes from runoff).

What lakes have algae blooms in Minnesota?

Algae blooms (especially blue-green / cyanobacteria) are most common in shallow, warm, nutrient-rich (eutrophic) lakes during late summer. Lakes with high phosphorus and chlorophyll-a measurements are at higher risk. The lakes on this page are filtered to exclude high-algae lakes. For the opposite list, see our most-polluted-lakes trend page.

When is it safe to swim in lakes in Minnesota?

Minnesota lakes are typically safest to swim in late spring through early summer (May–July), when water is cool and algae bloom risk is lowest. Risk rises in late summer and early fall (August–September) when warm water and accumulated nutrients drive cyanobacteria blooms. Always avoid swimming after heavy rainfall (bacterial spikes from runoff) and check current state DNR advisories the day you go.

What's the cleanest lake in Minnesota?

The single cleanest lake by combined water-quality score is featured on the Minnesota cleanest-lakes page. The lakes here are filtered specifically for swimming safety — same A/B grade requirement, plus low chlorophyll-a (active algae filter). For the broader cleanliness ranking, see /best/cleanest/mi.

Our swimming-safety filter

We don't just rank by overall grade. Lakes here have to pass three filters:

  • Grade A or B overall water quality (top 40% statewide)
  • Chlorophyll-a below 10 µg/L — actively low algae density, low risk of harmful blue-green blooms
  • Multi-year sampling data — excludes lakes with limited sampling history (data confidence)

The ranking within the filter is by combined water-quality score (Secchi clarity + phosphorus + chlorophyll-a). Always check current Minnesota DNR advisories before swimming.