Black Oak Lake

On the LakeGrade rubric, Black Oak Lake pulls an A: clarity at 28.5 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 33 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. Among the 191 graded lakes in Vilas County, Black Oak Lake ranks 16 — in the top quartile locally.

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.