Martha Lake

Martha Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year.

The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. At 55 ft of maximum depth, Martha Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. At 146 acres, Martha Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Within Iron County's 33 graded lakes, Martha Lake ranks 20 — below the local median, though not at the bottom.

No invasive species are currently listed at Martha Lake — the lake remains off the Wisconsin infested-waters roster. Walleye are documented at Martha 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.