Long Lake

On the LakeGrade rubric, Long Lake pulls an A: clarity at 46.6 ft and phosphorus readings still being added put it in the top bracket for 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. Long Lake is unusually deep for Minnesota at 115 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. At 1,007 acres, Long Lake is one of the larger lakes in Cass County, with 16.0 miles of shoreline supporting multiple distinct use patterns. Among the 133 graded lakes in Cass County, Long Lake sits at rank 38, above the county median.

Long Lake has no invasive species recorded in Minnesota state databases as of 2022, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 14 documented species — a notable draw for Minnesota anglers. A documented public access point at Long Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a long ice-out record — 57 observations on file, with a median ice-out around Apr 21. 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.