Long Lake

Long Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Bayfield County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

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. A maximum depth of 28 ft puts Long Lake in the middle of Wisconsin's depth distribution. Long Lake covers 280 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Bayfield County's 55 graded waters, Long Lake sits at rank 1, near the top of the local distribution.

Long Lake has at least one documented invasive species (Japanese knotweed), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. 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.