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.

Mesotrophic conditions dominate at Insula Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake's 63 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. Insula Lake covers 2,840 acres alongside 75.0 miles of shoreline, large enough that conditions can vary meaningfully between bays. Within Lake County's 142 graded lakes, Insula Lake ranks 96 — below the local median, though not at the bottom.

No invasive species are currently listed at Insula Lake — the lake remains off the Minnesota infested-waters roster. 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.