Loon Lake

Loon Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Barron County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 37 puts Loon Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. A maximum depth of 26 ft puts Loon Lake in the middle of Wisconsin's depth distribution. The lake is compact at 91 acres, with partial shoreline records and little volume to buffer nutrient inputs. Within Barron County's 38 graded waters, Loon Lake sits at rank 6, near the top of the local distribution.

Loon Lake has at least one documented invasive species (Chinese Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Loon Lake, one of 4 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.