Gannon Lake
St. Louis County, Minnesota93 acresView mapDirections
No nutrient or algae sampling on record from Minnesota PCA for this lake.
- Impaired · Mercury
- 18 ft max depth
Gannon Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Maximum depth: 18 ft. Surface area: 93 acres.
Gannon Lake is a 93-acre lake in St. Louis County, Minnesota with a maximum depth of 18 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. Gannon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Gannon 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 Gannon Lake
These are the measurements Minnesota PCA publishes for Gannon 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 Gannon Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
18 ft
Surface area
93 acres
Shoreline
2.6 mi
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Stays near Gannon Lake
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Fishing Gannon Lake
EPA Impairment Status
Gannon Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
Source: EPA ATTAINS assessment unit MN69-0819-00 · Official waterbody report
Nearby Lakes in St. Louis County
Frequently asked questions about Gannon Lake
Where is Gannon Lake?
- Gannon 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 Gannon Lake?
- Gannon Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Maximum depth: 18 ft. Surface area: 93 acres.
Is Gannon Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Gannon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Gannon Lake?
- Gannon Lake has a maximum depth of 18 feet. The lake covers 93 acres.
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Where this data comes from
Measurements for Gannon 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