Frog Lake

Frog Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Mesotrophic conditions dominate at Frog Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. Frog Lake reaches 38 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 53 acres, Frog Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Within Lake County's 142 graded lakes, Frog Lake ranks 78 — below the local median, though not at the bottom.

No invasive species are currently listed at Frog Lake — the lake remains off the Minnesota infested-waters roster. The fishery is bass-led, with 3 documented species across the lake's records. The lake lacks a documented public access point, so visitor use is limited. 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.