Mille Lacs Lake

Mille Lacs Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. Mille Lacs Lake reaches 42 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 128,250 acres, Mille Lacs Lake is one of the larger lakes in Aitkin County, with 105.5 miles of shoreline supporting multiple distinct use patterns. Among the 53 graded lakes in Aitkin County, Mille Lacs Lake ranks 12 — in the top quartile locally.

Zebra mussels have been documented at Mille Lacs Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Muskie are on the species list at Mille Lacs Lake, among the lake's 21 documented fish. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Mille Lacs Lake more than two dozen times, putting the median around Apr 25 — a useful baseline for tracking climate trends. 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.