Triangle Lake

Triangle 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.

Trophically, Triangle Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. A maximum depth of 43 ft puts Triangle Lake in the middle of Minnesota's depth distribution. Triangle Lake covers 300 acres alongside 10.4 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Lake County's 142 graded waters, Triangle Lake sits at rank 34, near the top of the local distribution.

Triangle Lake has no invasive species recorded in Minnesota state databases as of 2022, though prevention practices still apply at all access points. Walleye are documented at Triangle Lake, one of 7 fish species on record for the 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.