Namakan Lake

Namakan 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.

A TSI near 44 places Namakan Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. At 150 ft of maximum depth, Namakan Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. At 24,066 acres, Namakan Lake is one of the larger lakes in St. Louis County, with 319.9 miles of shoreline supporting multiple distinct use patterns. Among the 187 graded lakes in St. Louis County, Namakan Lake sits at rank 88, above the county median.

Namakan Lake has at least one documented invasive species (spiny waterflea), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. The fishery includes walleye alongside the lake's other 18 documented species — a notable draw for Minnesota anglers. 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.