Perch Lake

Perch Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

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. A maximum depth of 30 ft puts Perch Lake in the middle of Minnesota's depth distribution. Perch Lake covers 344 acres alongside 3.3 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 187 graded lakes in St. Louis County, Perch Lake ranks 38 — in the top quartile locally.

Perch Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Perch Lake, one of 10 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been recorded 9 times at Perch Lake, with a median around May 4. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.