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. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI value of 37 puts Deep Hole Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Deep Hole Lake reaches 22 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. Deep Hole Lake is small — 6 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Deep Hole Lake ranks 13 of 32 in Langlade County — solidly in the upper half of the local distribution.

Deep Hole Lake has at least one documented invasive species (Rusty Crayfish), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. The fishery is bass-led, with 2 documented species across the lake's records. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.