Upper Sugarbush Lake Deep

Upper Sugarbush Lake Deep earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Vilas 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 29 ft puts Upper Sugarbush Lake Deep in the middle of Wisconsin's depth distribution. Upper Sugarbush Lake Deep covers 141 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Upper Sugarbush Lake Deep ranks 29 of 191 in Vilas County, putting it in the upper tier of locally monitored lakes.

Upper Sugarbush Lake Deep has at least one documented invasive species (Rusty Crayfish), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. 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.