Sea Gull Lake

Sea Gull Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Cook County. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting 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. Sea Gull Lake ranks 33 of 128 in Cook County — solidly in the upper half 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.