Red Rock Lake

On the LakeGrade scale Red Rock Lake grades a B, with clarity at 12.7 ft and phosphorus readings still being added placing it above the Minnesota median. 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. Red Rock Lake is unusually deep for Minnesota at 64 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. At 451 acres, Red Rock Lake fits the Minnesota median for monitored lakes, with 12.9 miles of shoreline. Among the 128 graded lakes in Cook County, Red Rock Lake sits at rank 44, above the county median.

Red Rock Lake has at least one documented invasive species (spiny waterflea), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Red Rock Lake, one of 8 fish species on record for the lake. 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.