Loon Lake

On the LakeGrade rubric, Loon Lake pulls an A: clarity at 12.1 ft and 13 µg/L of phosphorus put it in the top bracket for Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. The lake bottoms out at 25 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 232 acres, Loon Lake fits the Minnesota median for monitored lakes, with 2.8 miles of shoreline. Within Cass County's 133 graded lakes, Loon Lake ranks 73 — below the local median, though not at the bottom.

Loon 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 Loon Lake, one of 12 fish species on record for the lake. A documented public access point at Loon Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.