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. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI near 43 places Mille Lacs Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. A maximum depth of 42 ft puts Mille Lacs Lake in the middle of Minnesota's depth distribution. With 128,250 acres of surface and 105.5 miles of shoreline, Mille Lacs Lake is a large water by Minnesota standards — recreational pressure is spread across a long shoreline. Mille Lacs Lake ranks 17 of 53 in Aitkin County — solidly in the upper half of the local distribution.

Zebra mussel presence at Mille Lacs Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Mille Lacs Lake's fishery is anchored by muskellunge, with 21 documented species in total — a destination water for muskie anglers. A documented public access point at Mille Lacs Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.