Rock River Lake

Rock River Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. 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 33 puts Rock River Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. Rock River Lake covers 548 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Rock River Lake ranks 1 of 4 in Rock County, putting it in the upper tier of locally monitored lakes.

No invasive species are currently listed at Rock River Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Rock River Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. 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.