Crystal Lake

On the LakeGrade rubric, Crystal Lake pulls an A: clarity at 16.0 ft and 7 µg/L of phosphorus put it in the top bracket for Minnesota. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

Trophically, Crystal Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake bottoms out at 40 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 190 acres and 3.5 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Cass County's 133 graded waters, Crystal Lake sits at rank 13, near the top of the local distribution.

Crystal 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 Crystal 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 8 times at Crystal Lake, with a median around Apr 16. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.