Deep Hole Lake

Deep Hole Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 30 puts Deep Hole Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Deep Hole Lake reaches 24 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. Deep Hole Lake is small — 37 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Deep Hole Lake ranks 32 of 140 in Oneida County, putting it in the upper tier of locally monitored lakes.

Deep Hole Lake has no invasive species recorded in Wisconsin state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Deep Hole Lake, one of 3 fish species on record for the lake. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.