Osnuhsa Lake

Osnuhsa Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. 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.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. Osnuhsa Lake is small — 6 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Osnuhsa Lake ranks 3 of 3 in Brown County — at the lower end of the locally monitored distribution.

Osnuhsa Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Osnuhsa Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The grade is supported by multiple sampling years from the Wisconsin DNR Citizen Lake Monitoring Network, giving the letter a reasonably stable foundation.