Oyster Lake
St. Louis County, Minnesota763 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Oyster Lake. Here is what has been measured.
- Impaired · Mercury
- 130 ft max depth
- Limited data
Oyster Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 6.6 ft visibility. Maximum depth: 130 ft. Surface area: 762.91 acres.
Minnesota DNR's Standard Survey on September 9, 1996 caught 2.17 northern pike per gill net at Oyster Lake. Length samples in the latest survey that recorded them ran 17–31 inches. DNR survey details →
Oyster Lake is a 763-acre lake in St. Louis County, Minnesota with a maximum depth of 130 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-07-26. Methodology: how these readings are compared.
What Oyster Lake is good for
From access and monitoring records, not editorial picks.
- Deep water130 ft surveyed max depth
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Oyster Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Oyster 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 Oyster Lake
These are the measurements Minnesota PCA publishes for Oyster Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 6.6 ft. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 50 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Oyster Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on September 9, 1996 caught 2.17 northern pike per gill net at Oyster Lake. Length samples in the latest survey that recorded them ran 17–31 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Oyster Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
4 surveys on file from MN DNR Fisheries. Most recent: 2025-07-29 (Targeted Survey).
4 surveys on file · most recent 2025-07-29 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Rock Bass | 3.50 | 4–8 in 1996-09-09 | 0.21 lb |
| White Sucker | 2.22 | 6–22 in 1996-09-09 | 2.03 lb |
| Tullibee (Cisco) | 1.79 | 6–9 in 1996-09-09 | 0.13 lb |
| Lake Trout | 1.25 | 10–28 in 1996-09-09 | 2.31 lb |
| Northern Pike | 0.71 | 17–31 in 1996-09-09 | 4.37 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Rock Bass
White Sucker
Tullibee (Cisco)
Lake Trout
From the 2025-07-29 survey
Temperature and dissolved oxygen (DO) measurements were collected from the deepest basin in Oyster Lake on July 29th, 2025, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake (Cisco, also known as…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Oyster Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OysterFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
130 ft
Surface area
763 acres
Shoreline
8.7 mi
Littoral zone
31%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
15 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,224 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Oyster Lake
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Top-rated places to stay near Oyster Lake
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Follow Oyster Lake’s readings
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Fishing Oyster Lake
Water quality readings over time
2 seasons of samples on record (2022–2025). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
EPA Impairment Status
Oyster 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 MN69-0330-00 · Official waterbody report
Nearby Lakes in St. Louis County
Frequently asked questions about Oyster Lake
Where is Oyster Lake?
- Oyster 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 Oyster Lake?
- Oyster Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 6.6 ft visibility. Maximum depth: 130 ft. Surface area: 762.91 acres.
Is Oyster Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Oyster Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Oyster Lake?
- Oyster Lake has a maximum depth of 130 feet. The lake covers 762.91 acres.
What did the DNR fisheries survey find at Oyster Lake?
- Minnesota DNR's Standard Survey on September 9, 1996 caught 2.17 northern pike per gill net at Oyster Lake. Length samples in the latest survey that recorded them ran 17–31 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Oyster Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Oyster Lake?
- Public access to Oyster Lake is listed as no on the lake record, so confirm before you make the trip. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Oyster Lake across LakeQuality
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Where this data comes from
2 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA2 samples · 2022–2025
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder