Insula Lake

Insula Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. 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.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. At 63 ft of maximum depth, Insula Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Insula Lake covers 2,840 acres alongside 75.0 miles of shoreline, large enough that conditions can vary meaningfully between bays. Insula Lake sits at rank 96 of 142 in Lake County, in the lower half of the local distribution.

Insula Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Insula Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. 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.