Dark Lake

Dark Lake earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer. 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.

At a TSI of 58, Dark Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake bottoms out at 31 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Dark Lake covers 231 acres alongside 3.9 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within the 215 graded lakes of St. Louis County, Dark Lake sits at rank 192, near the bottom of the county list.

No invasive species are currently listed at Dark Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 10 documented species — a notable draw for Minnesota anglers. A documented public access point at Dark Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.