Four Lake
Lake County, Minnesota611 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Four Lake. Here is what has been measured.
- Impaired · Mercury
- 25 ft max depth
- Limited data
Four Lake in Lake County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 8 ft visibility. Maximum depth: 25 ft. Surface area: 610.88 acres.
Minnesota DNR's Standard Survey on June 19, 2017 caught 3.56 walleye per gill net at Four Lake. Length samples in the latest survey that recorded them ran 7–16 inches. DNR survey details →
Four Lake is a 611-acre lake in Lake County, Minnesota with a maximum depth of 25 feet. Overall water quality is improving over recent sampling years. The lake supports 9 documented fish species including bluegill, cisco species, and lake whitefish. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-03. Methodology: how these readings are compared.
What Four Lake is good for
From access and monitoring records, not editorial picks.
- Fishing9 species recorded
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Four Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Four 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 Four Lake
These are the measurements Minnesota PCA publishes for Four 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 8 ft. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8ft | 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. | 47 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Four Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on June 19, 2017 caught 3.56 walleye per gill net at Four Lake. Length samples in the latest survey that recorded them ran 7–16 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Four Lake’s water-quality measurements separately, and the water-quality trend over 3 years of monitoring is improving. 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: 2017-06-19 (Standard Survey).
2 surveys on file · most recent 2017-06-19 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| White Sucker | 5.50 | 13–21 in 2017-06-19 | 1.96 lb |
| Walleye | 4.05 | 7–16 in 2017-06-19 | 0.71 lb |
| Northern Pike | 3.71 | 11–40 in 2017-06-19 | 2.35 lb |
| Yellow Perch | 2.44 | 5–9 in 2017-06-19 | 0.12 lb |
| Rock Bass | 1.15 | 4–7 in 2017-06-19 | 0.18 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.
White Sucker
Walleye
Northern Pike
Yellow Perch
From the 2017-06-19 survey
Lake Four is located within the Boundary Waters Canoe Area Wilderness (BWCAW) within the Superior National Forest and is a non-motorized lake. It is approximately 20 miles east of Ely. It is a 611 acre lake with a maximum depth of 25 feet and has brown water. The surrounding landscape of the southern part of Lake Four…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Four Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — FourFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
25 ft
Surface area
611 acres
Shoreline
22.9 mi
Littoral zone
84%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
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Stays near Four Lake
Compare lakeside cabins, hotels, and vacation rentals near Four Lake in Lake 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.
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Fish Species
Click a species to see every lake where it is documented.
Fishing Four Lake
Water quality readings over time
3 seasons of samples on record (2020–2025). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving3 years
EPA Impairment Status
Four 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 MN38-0528-00 · Official waterbody report
Nearby Lakes in Lake County
Frequently asked questions about Four Lake
Where is Four Lake?
- Four Lake is a lake in Lake County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Four Lake?
- Four Lake in Lake County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 8 ft visibility. Maximum depth: 25 ft. Surface area: 610.88 acres.
Is Four Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Four Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
How deep is Four Lake?
- Four Lake has a maximum depth of 25 feet. The lake covers 610.88 acres.
What fish are in Four Lake?
- Fish species found in Four Lake include bluegill, cisco species, lake whitefish, northern pike, rock bass, smallmouth bass, walleye, white sucker, yellow perch. Four Lake is located in Lake County, Minnesota.
What did the DNR fisheries survey find at Four Lake?
- Minnesota DNR's Standard Survey on June 19, 2017 caught 3.56 walleye per gill net at Four Lake. Length samples in the latest survey that recorded them ran 7–16 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Four Lake’s water-quality measurements separately, and the water-quality trend over 3 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Four Lake?
- Public access to Four 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 Four Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Lake County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Lake Superior Basin (MN+WI), ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
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Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
5 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA5 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (3)
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 details from Minnesota DNR LakeFinder