Manitowish Lake

Manitowish Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. 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 value of 23 puts Manitowish Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's 61 ft maximum depth is in the upper tier for Wisconsin — deep enough for cold-water fish to find refuge in summer. At 496 acres, Manitowish Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Among the 202 graded lakes in Vilas County, Manitowish Lake sits at rank 78, above the county median.

Manitowish Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. Walleye are documented at Manitowish Lake, one of 6 fish species on record for the lake. 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.