Loon Lake

Loon Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

Trophically, Loon Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. At 63 ft of maximum depth, Loon Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. The lake is compact at 50 acres, with partial shoreline records and little volume to buffer nutrient inputs. Among the 48 graded lakes in Washburn County, Loon Lake ranks 10 — in the top quartile locally.

No invasive species are currently listed at Loon Lake — the lake remains off the Wisconsin infested-waters roster. Bass fishing is part of the appeal: the species list runs to 2, anchored by largemouth and/or smallmouth bass. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.