Long Lake

On the LakeGrade rubric, Long Lake pulls an A: clarity at 21.5 ft and phosphorus readings still being added put it in the top bracket for Minnesota.

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. The lake's 115 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. With 1,007 acres of surface and 16.0 miles of shoreline, Long Lake is a large water by Minnesota standards — recreational pressure is spread across a long shoreline. Among the 132 graded lakes in Cass County, Long Lake sits at rank 38, above the county median.

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 14 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Long Lake more than two dozen times, putting the median around Apr 21 — a useful baseline for tracking climate trends. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.