Oslo Lake
St. Louis County, Minnesota99 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Oslo Lake. Here is what has been measured.
- Impaired · Mercury
- 36 ft max depth
- Limited data
Oslo Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9.2 ft visibility. Maximum depth: 36 ft. Surface area: 99.24 acres.
Minnesota DNR's Standard Survey on July 14, 2025 caught 7.83 northern pike per gill net at Oslo Lake. Length samples in the latest survey that recorded them ran 11–24 inches. DNR survey details →
Oslo Lake is a 99-acre lake in St. Louis County, Minnesota with a maximum depth of 36 feet. Overall water quality is declining over recent sampling years. The lake supports 2 documented fish species including northern pike and yellow perch. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-08-08. Methodology: how these readings are compared.
Oslo Lake covers about 99 acres in St. Louis County. If you are planning to stay, you can search lake houses and cabins around Oslo Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Oslo Lake is good for
From access and monitoring records, not editorial picks.
- Deep water36 ft surveyed max depth
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Oslo Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Oslo 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 Oslo Lake
These are the measurements Minnesota PCA publishes for Oslo Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9.2 ft. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9.2ft | 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. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Oslo Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on July 14, 2025 caught 7.83 northern pike per gill net at Oslo Lake. Length samples in the latest survey that recorded them ran 11–24 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Oslo Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 2025-07-14 (Standard Survey).
2 surveys on file · most recent 2025-07-14 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Northern Pike | 5.67 | 11–24 in 2025-07-14 | 1.61 lb |
| Yellow Perch | 0.25 | 5 in 2025-07-14 | 0.09 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.
Northern Pike
Yellow Perch
From the 2025-07-14 survey
Oslo Lake is located approximately eight miles west of Kettle Falls, Minnesota. This 99.2-acre lake has a maximum depth of 36 feet and dark tannin-stained water. A fisheries survey was completed in Oslo Lake during the 2025 field season as part of a regular rotation of surveys in the International Falls Management…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Oslo Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OsloFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
36 ft
Surface area
99 acres
Shoreline
3.7 mi
Littoral zone
58%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,178 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Oslo Lake
Compare lakeside cabins, hotels, and vacation rentals near Oslo Lake in St. Louis County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Oslo Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Follow Oslo Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Oslo Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Stable5 years
Phosphorus
Worsening+2.17 µg/L/yr4 years
EPA Impairment Status
Oslo 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 MN69-0838-00 · Official waterbody report
Nearby Lakes in St. Louis County
Frequently asked questions about Oslo Lake
Where is Oslo Lake?
- Oslo 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 Oslo Lake?
- Oslo Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9.2 ft visibility. Maximum depth: 36 ft. Surface area: 99.24 acres.
Is Oslo Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Oslo Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Oslo Lake?
- Oslo Lake has a maximum depth of 36 feet. The lake covers 99.24 acres.
What fish are in Oslo Lake?
- Fish species found in Oslo Lake include northern pike, yellow perch. Oslo Lake is located in St. Louis County, Minnesota.
What did the DNR fisheries survey find at Oslo Lake?
- Minnesota DNR's Standard Survey on July 14, 2025 caught 7.83 northern pike per gill net at Oslo Lake. Length samples in the latest survey that recorded them ran 11–24 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Oslo Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Oslo Lake?
- Public access to Oslo 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.
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Where this data comes from
1 measurement from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Minnesota Water Science Center
USGS-MN1 sample · 2023
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