Larson Lake

Larson Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. 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.

A TSI value of 29 puts Larson Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. At 177 ft of maximum depth, Larson Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Larson Lake covers 208 acres alongside 3.8 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 141 graded lakes in Itasca County, Larson Lake ranks 29 — in the top quartile locally.

No invasive species are currently listed at Larson Lake — the lake remains off the Minnesota infested-waters roster. The lake's fish records list 6 species — a varied community without one dominant gamefish. Public access is available — the lake is on the Minnesota PCA public-access list. 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.