Shannon Lake

Shannon Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Wisconsin norms.

A TSI near 47 places Shannon Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. A maximum depth of 30 ft puts Shannon Lake in the middle of Wisconsin's depth distribution. Shannon Lake is small — 35 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within Vilas County's 191 graded lakes, Shannon Lake ranks 111 — below the local median, though not at the bottom.

Shannon Lake has no invasive species recorded in Wisconsin state databases as of 2022, though prevention practices still apply at all access points. The fishery is bass-led, with 3 documented species across the lake's records. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.