Presque Isle Lake

Presque Isle 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'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's 103 ft maximum depth is in the upper tier for Wisconsin — deep enough for cold-water fish to find refuge in summer. Presque Isle Lake covers 1,165 acres alongside partial shoreline records, large enough that conditions can vary meaningfully between bays. Within Vilas County's 191 graded waters, Presque Isle Lake sits at rank 18, near the top of the local distribution.

Presque Isle Lake has at least one documented invasive species (Rusty Crayfish), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Presque Isle Lake, one of 6 fish species on record for the lake. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.