Long Lake

Long 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 Long Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. Long Lake reaches 47 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 423 acres, Long Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Long Lake ranks 4 of 10 in Fond du Lac County — solidly in the upper half of the local distribution.

Long 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 among the lake's 4 documented species — a notable draw for Wisconsin anglers. 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.