Round Lake

Round 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.

Trophically, Round Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake bottoms out at 45 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 154 acres, Round Lake fits the Minnesota median for monitored lakes, with 2.7 miles of shoreline. Round Lake ranks 3 of 128 in Cook County, putting it in the upper tier of locally monitored lakes.

Round 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 Round Lake, one of 5 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.