Sioux Lake

On the LakeGrade rubric, Sioux Lake pulls an A: clarity readings still being added and phosphorus readings still being added put it in the top bracket for 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. Sioux Lake reaches 34 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. Sioux Lake is small — 71 acres alongside 1.7 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Among the 141 graded lakes in Itasca County, Sioux Lake sits at rank 39, above the county median.

Sioux Lake has no invasive species recorded in Minnesota state databases as of 2019, though prevention practices still apply at all access points. The fishery is bass-led, with 8 documented species across the lake's records. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.