Johnson Lake

On the LakeGrade scale Johnson Lake grades a B, with clarity at 11.5 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. The lake bottoms out at 24 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Johnson Lake is small — 36 acres alongside 1.3 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Among the 142 graded lakes in Lake County, Johnson Lake sits at rank 49, above the county median.

Johnson Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Minnesota anglers. No formal public access is documented at Johnson Lake — most use is by shoreline residents and their guests. The lake has a long ice-out record — 51 observations on file, with a median ice-out around May 2. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.