Round Lake

Round Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 39 puts Round Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's 125 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. The lake's 737 acres and 5.0 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Aitkin County's 53 graded waters, Round Lake sits at rank 7, near the top of the local distribution.

Zebra mussel presence at Round Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Walleye are documented at Round Lake, one of 18 fish species on record for the lake. A documented public access point at Round Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a partial ice record — 7 observed ice-outs, centered near Apr 14. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.