Cranberry Lake

On the LakeGrade rubric, Cranberry Lake pulls an A: clarity at 27.9 ft and 14 µg/L of phosphorus put it in the top bracket for Wisconsin. 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. The lake bottoms out at 26 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 66 acres, Cranberry Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within Burnett County's 70 graded waters, Cranberry Lake sits at rank 12, near the top of the local distribution.

Cranberry Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.