Sturgeon Lake

Sturgeon Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in St. Louis County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

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. Sturgeon Lake is unusually deep for Minnesota at 80 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. At 1,585 acres, Sturgeon Lake is one of the larger lakes in St. Louis County, with 10.8 miles of shoreline supporting multiple distinct use patterns. Within St. Louis County's 187 graded waters, Sturgeon Lake sits at rank 41, near the top of the local distribution.

Sturgeon Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 15 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 Sturgeon Lake more than two dozen times, putting the median around Apr 25 — 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.