Fourmile Lake

Fourmile Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. A maximum depth of 29 ft puts Fourmile Lake in the middle of Wisconsin's depth distribution. Fourmile Lake covers 210 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Oneida County's 134 graded lakes, Fourmile Lake ranks 97 — below the local median, though not at the bottom.

Fourmile 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 includes walleye alongside the lake's other 6 documented species — a notable draw for Wisconsin anglers. 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.