Long Lake

On the LakeGrade scale Long Lake grades a B, with clarity at 13.5 ft and phosphorus readings still being added placing it above the Minnesota median.

A TSI value of 40 puts Long Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake bottoms out at 33 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Long Lake covers 150 acres alongside 4.0 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within St. Louis County's 187 graded waters, Long Lake sits at rank 46, near the top of the local distribution.

No invasive species are currently listed at Long Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye among the lake's 8 documented species — a notable draw for Minnesota anglers. No formal public access is documented at Long Lake — most use is by shoreline residents and their guests. The lake has a partial ice record — 15 observed ice-outs, centered near Apr 21. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.