Best Trout Lakes in Minnesota & Wisconsin
Trout require the coldest, cleanest, most oxygen-rich lakes. Finding trout is one of the strongest indicators of excellent water quality. These are the top trout lakes ranked by overall water quality grade.
| Rank | Lake | County | State | Grade | Clarity | Depth | Trout Species |
|---|
Why Trout Need Clean Water
Trout are cold-water species with the highest dissolved oxygen requirements of any freshwater fish. They need water temperatures below 68°F (20°C) and dissolved oxygen above 7 mg/L to survive. These conditions are only found in deep, clean lakes — typically those graded A or B.
As water quality declines (grades C through F), warmer surface water and nutrient-driven algae blooms deplete oxygen in the cold, deep water trout depend on. This is why trout are often the first species to disappear from a lake as pollution increases.
Trout Species in the Region
- Lake Trout — the apex coldwater predator, found only in the deepest, cleanest lakes with year-round cold water below the thermocline
- Brook Trout — native char that requires the coldest, most pristine waters. Very sensitive to any water quality degradation
- Brown Trout — slightly more tolerant than brook trout but still requires clean, cold, well-oxygenated water
- Rainbow Trout — often stocked, can tolerate slightly warmer water than other trout but still needs good water quality
- Splake — a hybrid of brook trout and lake trout, stocked in some lakes for sport fishing