Black Oak Lake

On the LakeGrade rubric, Black Oak Lake pulls an A: clarity at 88.6 ft and 10 µg/L of phosphorus put it in the top bracket for Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

A TSI value of 25 puts Black Oak Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's 85 ft maximum depth is in the upper tier for Wisconsin — deep enough for cold-water fish to find refuge in summer. At 564 acres, Black Oak Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Black Oak Lake ranks 69 of 202 in Vilas County — solidly in the upper half of the local distribution.

An invasive species record — Chinese Mystery Snail — has been logged at Black Oak Lake; Wisconsin DNR maintains the official infested-waters list. Walleye are documented at Black Oak 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.