Leighton Lake

Leighton Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. Leighton Lake is unusually deep for Minnesota at 63 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 245 acres and 4.1 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Among the 141 graded lakes in Itasca County, Leighton Lake sits at rank 37, above the county median.

No invasive species are currently listed at Leighton Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 11 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.