Three Island Lake

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

Trophically, Three Island Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. At 66 ft of maximum depth, Three Island Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Three Island Lake covers 250 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, Three Island Lake ranks 23 — in the top quartile locally.

No invasive species are currently listed at Three Island Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Three Island Lake, one of 7 fish species on record for the lake. No formal public access is documented at Three Island Lake — most use is by shoreline residents and their guests. 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.