Where is Fishmouth Lake?

Fishmouth 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.

How deep is Fishmouth Lake?

Fishmouth Lake has a maximum depth of 26.3 feet. The lake covers 31 acres.

Fishmouth Lake

St. Louis County, Minnesota31 acresView map Directions

No nutrient or algae sampling on record from Minnesota PCA for this lake.

Max depth

26.3 ft

Bathymetric survey

Area

31 acres

Surface area

Shoreline

1.2 mi

Measured length

Impaired · Mercury
26 ft max depth

See the measurements Directions Where to stay

Fishmouth Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Maximum depth: 26.3 ft. Surface area: 31 acres.

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Fishmouth Lake is a 31-acre lake in St. Louis County, Minnesota with a maximum depth of 26 feet.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder. Methodology: how these readings are compared.

Swimming conditions

No reading

Not rated

Nutrient and algae readings are not a swimming clearance. Fishmouth Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.

Whether Fishmouth 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.

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Water quality measurements for Fishmouth Lake

These are the measurements Minnesota PCA publishes for Fishmouth 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.

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Answers come straight from the public measurements and survey records on this page.

Lake Details

Max depth

26.3 ft

Surface area

31 acres

Shoreline

1.2 mi

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Stays near Fishmouth Lake

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Fishing Fishmouth Lake

→ Fishmouth Lake fishing regulations (limits, seasons, special rules)

EPA Impairment Status

Fishmouth Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Mercury

Designated uses not supporting: Fish consumption.

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN69-0834-00 · Official waterbody report

Nearby Lakes in St. Louis County

Peary Lake6.7 ft clear · Mesotrophic0.5 miView →Brown Lake8.5 ft clear · Mesotrophic1 miView →Oslo Lake9.2 ft clear1.4 miView →Beast Lake10.2 ft clear1.6 miView →Cruiser Lake25.4 ft clear · Oligotrophic2.5 miView →McDivitt Lake2.2 miView →

Frequently asked questions about Fishmouth Lake

Where is Fishmouth Lake?: Fishmouth 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 Fishmouth Lake?: Fishmouth Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Maximum depth: 26.3 ft. Surface area: 31 acres.
Is Fishmouth Lake safe to swim in?: Nutrient and algae readings are not a swimming clearance. Fishmouth Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
How deep is Fishmouth Lake?: Fishmouth Lake has a maximum depth of 26.3 feet. The lake covers 31 acres.