Big Lake

Big Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. 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 Wisconsin lakes fall. Big Lake reaches 30 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. Big Lake covers 780 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Big Lake ranks 8 of 191 in Vilas County, putting it in the upper tier of locally monitored lakes.

Big Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. The fishery includes walleye alongside the lake's other 6 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.