Rocky Lake

Rocky 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.

Mesotrophic conditions dominate at Rocky Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. A maximum depth of 40 ft puts Rocky Lake in the middle of Minnesota's depth distribution. Rocky Lake covers 120 acres alongside 3.3 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Rocky Lake sits at rank 143 of 215 in St. Louis County, in the lower half of the local distribution.

Rocky Lake has no invasive species recorded in Minnesota state databases as of 2025, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Rocky 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.