Mill Lake

Mill Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.

A TSI near 46 places Mill Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. Mill Lake reaches 40 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake's 271 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. Among the 35 graded lakes in Walworth County, Mill Lake sits at rank 12, above the county median.

Mill Lake is on the Wisconsin infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. A documented public access point at Mill Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.