Hay Lake

Hay Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. 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.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. At 56 ft of maximum depth, Hay Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. At 364 acres, Hay Lake fits the Minnesota median for monitored lakes, with 5.2 miles of shoreline. Within Cass County's 133 graded lakes, Hay Lake ranks 76 — below the local median, though not at the bottom.

No invasive species are currently listed at Hay Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Hay Lake, one of 14 fish species on record for the lake. A documented public access point at Hay Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.