Heart Lake

Heart 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 37 puts Heart Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. At 55 ft of maximum depth, Heart Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. The lake's 224 acres and 3.5 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Clearwater County's 40 graded waters, Heart Lake sits at rank 3, near the top of the local distribution.

No invasive species are currently listed at Heart Lake — the lake remains off the Minnesota infested-waters roster. Bass fishing is part of the appeal: the species list runs to 5, anchored by largemouth and/or smallmouth bass. The lake lacks a documented public access point, so visitor use is limited. 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.