Iron Lake

Iron Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. Iron Lake reaches 19 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 122 acres, Iron Lake fits the Minnesota median for monitored lakes, with 7.2 miles of shoreline. Within Cook County's 137 graded lakes, Iron Lake ranks 78 — below the local median, though not at the bottom.

No invasive species are currently listed at Iron Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 8 documented species — a notable draw for Minnesota anglers. 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.