Butternut Lake

Butternut Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Forest County. 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 bottoms out at 42 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 1,246 acres, Butternut Lake is one of the larger lakes in Forest County, with partial shoreline records supporting multiple distinct use patterns. Among the 35 graded lakes in Forest County, Butternut Lake sits at rank 9, above the county median.

Butternut Lake has at least one documented invasive species (Banded Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Butternut Lake, one of 4 fish species on record for the lake. A documented public access point at Butternut Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.