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.

Mesotrophic conditions dominate at Red Rock Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake's 64 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. Red Rock Lake covers 451 acres alongside 12.9 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 128 graded lakes in Cook County, Red Rock Lake sits at rank 43, above the county median.

An invasive species record — spiny waterflea — has been logged at Red Rock Lake; Minnesota PCA maintains the official infested-waters list. The fishery includes walleye among the lake's 8 documented species — a notable draw for Minnesota anglers. The lake lacks a documented public access point, so visitor use is limited. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.