Spearhead Lake

Spearhead 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 38 puts Spearhead Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Spearhead Lake is unusually deep for Minnesota at 81 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 194 acres and 3.9 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Spearhead Lake ranks 3 of 76 in Hubbard County, putting it in the upper tier of locally monitored lakes.

Spearhead Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Spearhead Lake, one of 17 fish species on record for the lake. 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.