Little Johnson Lake
St. Louis County, Minnesota561 acresView mapDirections
No nutrient or algae sampling on record from Minnesota PCA for this lake.
- Impaired · Mercury
- 28 ft max depth
Little Johnson Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Maximum depth: 27.7 ft. Surface area: 561 acres.
Little Johnson Lake is a 561-acre lake in St. Louis County, Minnesota with a maximum depth of 28 feet.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder. Methodology: how these readings are compared.
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Little Johnson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Little Johnson Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Little Johnson Lake
These are the measurements Minnesota PCA publishes for Little Johnson Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. TSI undefined.
Ask about Little Johnson Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
27.7 ft
Surface area
561 acres
Shoreline
9.5 mi
The depth above comes from a bathymetric survey of this lake, not from a regional estimate.
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Fishing Little Johnson Lake
EPA Impairment Status
Little Johnson Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN69-0760-00 · Official waterbody report
Nearby Lakes in St. Louis County
Frequently asked questions about Little Johnson Lake
Where is Little Johnson Lake?
- Little Johnson Lake is a lake in St. Louis County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Little Johnson Lake?
- Little Johnson Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Maximum depth: 27.7 ft. Surface area: 561 acres.
Is Little Johnson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Little Johnson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
How deep is Little Johnson Lake?
- Little Johnson Lake has a maximum depth of 27.7 feet. The lake covers 561 acres.
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Where this data comes from
Measurements for Little Johnson Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake details from Minnesota DNR LakeFinder