Flannery Lake

Flannery 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 40 puts Flannery Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake bottoms out at 35 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 107 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. Within Oneida County's 134 graded waters, Flannery Lake sits at rank 28, near the top of the local distribution.

No invasive species are currently listed at Flannery Lake — the lake remains off the Wisconsin infested-waters roster. The fishery is bass-led, with 2 documented species across the lake's records. A documented public access point at Flannery Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.