Best Swimming Lakes in Minnesota & Wisconsin
Top 50 lakes safe for swimming — 25 from each state. Filtered for grade A or B water, chlorophyll-a below 10 µg/L (low algae bloom risk), and consistent multi-year sampling. Ranked by overall water quality score.
State-specific lists: Minnesota → Wisconsin → Related: Cleanest lakes → Swimming safety guide →
| Rank | Lake | County | State | Grade | Clarity | Algae | Area |
|---|---|---|---|---|---|---|---|
| 1 | East Fox Lake | Crow Wing | MN | A | 16.1 ft | — | 240.88 acres |
| 2 | Deep Portage Lake | Cass | MN | A | 15.4 ft | — | 129.02 acres |
| 3 | Little Wabana Lake | Itasca | MN | A | 23.8 ft | — | 115.73 acres |
| 4 | Clearwater Lake | Cook | MN | A | 30 ft | — | 461.73 acres |
| 5 | Lower Hay Lake | Crow Wing | MN | A | 19 ft | — | 700.21 acres |
| 6 | Latoka Lake | Douglas | MN | A | 19 ft | — | 766.63 acres |
| 7 | Bad Medicine Lake | Becker | MN | A | 25 ft | — | 803.03 acres |
| 8 | Big Sugar Bush Lake | Becker | MN | A | 17 ft | — | 521.51 acres |
| 9 | Pelican Lake | Otter Tail | MN | A | 16.1 ft | — | 4.0K acres |
| 10 | Fullers Lake: East Basin | Beltrami | MN | A | 15 ft | — | - |
| 11 | Birch Lake | Wright | MN | A | 15 ft | — | 99.82 acres |
| 12 | Birch Lake | Cook | MN | A | 18 ft | — | 236.31 acres |
| 13 | Round Lake | Cook | MN | A | 16.5 ft | — | 154.48 acres |
| 14 | Round Lake | Beltrami | MN | A | 18 ft | — | 181.06 acres |
| 15 | Pike Lake | Cook | MN | A | 17.8 ft | — | 814.43 acres |
| 16 | Whitefish Lake | Crow Wing | MN | A | 15.1 ft | — | 7.7K acres |
| 17 | Long Lake | Clearwater | MN | A | 20 ft | — | 158.86 acres |
| 18 | Long Lake | Cass | MN | A | 21.5 ft | — | 1.0K acres |
| 19 | Long Lake | Beltrami | MN | A | 20 ft | — | 411.95 acres |
| 20 | Long Lake | Becker | MN | A | 20 ft | — | 414.51 acres |
| 21 | Long Lake | Itasca | MN | A | 16.7 ft | — | 155.28 acres |
| 22 | Long Lake | Itasca | MN | A | 16.9 ft | — | 134.49 acres |
| 23 | Dead Lake | Hubbard | MN | A | 16 ft | — | 130.64 acres |
| 24 | Unnamed Lake | Otter Tail | MN | A | 15.1 ft | — | 1.4K acres |
| 25 | Maple Lake | Itasca | MN | A | 15.3 ft | — | 254.55 acres |
| 26 | Geneva Lake | Walworth | WI | A | 20.2 ft | — | 5.4K acres |
| 27 | Round Lake | Sawyer | WI | A | 21.1 ft | 1 µg/L | 3.3K acres |
| 28 | Round Lake | Oconto | WI | A | 16.8 ft | — | 31 acres |
| 29 | Deep Lake | Adams | WI | A | 15.5 ft | — | 33 acres |
| 30 | Beasley Lake | Waupaca | WI | A | 18.4 ft | — | 12 acres |
| 31 | Bass Lake | Washburn | WI | A | 16 ft | — | 132 acres |
| 32 | Bass Lake | Oconto | WI | A | 16.8 ft | — | 145 acres |
| 33 | Clear Lake | Sawyer | WI | A | 17 ft | — | 77 acres |
| 34 | Clear Lake | Polk | WI | A | 15.5 ft | — | 30 acres |
| 35 | Clear Lake | Lincoln | WI | A | 18 ft | — | 259 acres |
| 36 | Explosion Lake | Oconto | WI | A | 17 ft | — | 43 acres |
| 37 | Sugar Camp Lake | Oneida | WI | A | 16.5 ft | — | - |
| 38 | Little Spider Lake | Vilas | WI | A | 16 ft | — | 223 acres |
| 39 | Rosalind Lake | Vilas | WI | A | 19.3 ft | — | - |
| 40 | Lake Lucerne | Forest | WI | A | 18.5 ft | — | 1.0K acres |
| 41 | Two Island Lake | Chippewa | WI | A | 15.3 ft | — | 29 acres |
| 42 | Long Lake | Bayfield | WI | A | 16.2 ft | — | 280 acres |
| 43 | Long Lake | Burnett | WI | A | 21.5 ft | — | 222 acres |
| 44 | Lake Metonga | Forest | WI | A | 22 ft | — | 2.0K acres |
| 45 | Anderson Lake | Vilas | WI | A | 21 ft | — | 35 acres |
| 46 | Archibald Lake | Oconto | WI | A | 17.6 ft | — | 392 acres |
| 47 | Carlin Lake | Vilas | WI | A | 21 ft | — | 155 acres |
| 48 | Wolf Lake | Adams | WI | A | 15 ft | — | 42 acres |
| 49 | Butternut Lake | Forest | WI | A | 19.5 ft | — | 1.2K acres |
| 50 | Green Lake | Oconto | WI | A | 18.3 ft | — | 21 acres |
Frequently Asked Questions
How do you know if a lake is safe to swim?
Three signals matter most: water clarity (Secchi depth — clearer water has less suspended sediment and pathogens), chlorophyll-a (low values mean low algae density), and posted advisories from the state DNR or county health department. Lakes here all have grade A or B, chlorophyll-a below 10 µg/L, and pass our combined safety filter — but always check posted advisories the day you visit.
What is the 80/20 rule in swimming?
The 80/20 rule is a swim-training concept (80% easy aerobic work, 20% high intensity), unrelated to water quality. For lake-swimming safety, the relevant rule is the EPA recreational water guideline: total bacteria below 235 colonies per 100 mL for primary contact recreation.
What lakes are you not allowed to swim in?
Most US lakes allow swimming, but specific lakes may be closed seasonally for harmful algal blooms (HABs), elevated bacteria, or storm runoff. State DNRs and county health departments post advisories. Some reservoirs prohibit swimming year-round (drinking water sources, hazardous bottom conditions, restricted access). The lakes ranked here are all open public-access lakes with consistently safe water quality.
What are the risks of swimming in a lake?
The main risks are: (1) blue-green algae blooms (cyanobacteria) which produce toxins that cause skin irritation, gastrointestinal illness, or worse if swallowed; (2) bacterial contamination after heavy rain (E. coli from agricultural or sewage runoff); (3) underwater hazards like submerged rocks, weeds, or sudden depth changes. Swimmer safety: never swim alone, check advisories, avoid swimming after heavy rain, and stay out of visibly green or scummy water.
Can you get sick from swimming in a lake?
Yes — though it's rare in well-monitored lakes. The most common illnesses are gastrointestinal (from swallowing water with E. coli or other bacteria), skin rashes (from blue-green algae toxins), and ear infections. Swim in lakes with grade A or B water, avoid swallowing water, rinse off after swimming, and check posted advisories. The lakes ranked above are filtered for low algae and good clarity.