Cranberry Lake

Cranberry Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Trophically, Cranberry Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. Cranberry Lake covers 131 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Cranberry Lake ranks 15 of 55 in Bayfield County — solidly in the upper half of the local distribution.

Cranberry Lake has no invasive species recorded in Wisconsin state databases as of 2021, though prevention practices still apply at all access points. Walleye are documented at Cranberry Lake, one of 5 fish species on record for the lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.