Pine Lake

Pine Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota.

A TSI value of 35 puts Pine Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. At 113 ft of maximum depth, Pine Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. With 2,122 acres of surface and 18.2 miles of shoreline, Pine Lake is a large water by Minnesota standards — recreational pressure is spread across a long shoreline. Within Cook County's 128 graded waters, Pine Lake sits at rank 8, near the top of the local distribution.

An invasive species record — spiny waterflea — has been logged at Pine Lake; Minnesota PCA maintains the official infested-waters list. The fishery includes walleye among the lake's 10 documented species — a notable draw for Minnesota anglers. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.