Peter Lake

On the LakeGrade rubric, Peter Lake pulls an A: clarity at 22.5 ft and phosphorus readings still being added put it in the top bracket for Minnesota.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. Peter Lake is unusually deep for Minnesota at 120 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 282 acres and 6.7 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Among the 128 graded lakes in Cook County, Peter Lake ranks 18 — in the top quartile locally.

Peter Lake has no invasive species recorded in Minnesota state databases as of 2020, though prevention practices still apply at all access points. 4 fish species are documented at Peter Lake, a mixed warm-water community typical for Minnesota lakes of this size. No formal public access is documented at Peter Lake — most use is by shoreline residents and their guests. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.