Sea Gull Lake

Sea Gull Lake earns an A — every scored parameter (clarity and phosphorus) rates among the best monitored waters in Cook County. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.

A TSI value of 35 puts Sea Gull Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Sea Gull Lake reaches 40 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. Sea Gull Lake covers 168 acres alongside 7.2 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Cook County's 128 graded waters, Sea Gull Lake sits at rank 32, near the top of the local distribution.

Sea Gull Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Sea Gull Lake, one of 12 fish species on record for the lake. 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.