Spirit Lake

Spirit Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Oneida County. 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 32 puts Spirit Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. A maximum depth of 39 ft puts Spirit Lake in the middle of Wisconsin's depth distribution. The lake's 348 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Spirit Lake ranks 11 of 140 in Oneida County, putting it in the upper tier of locally monitored lakes.

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