One Pine Lake
St. Louis County, Minnesota354 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for One Pine Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- 13 ft max depth
- Public access
- Limited data
One Pine Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.5 ft visibility. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 8.6 µg/L. Maximum depth: 13 ft. Surface area: 353.54 acres.
Minnesota DNR's Standard Survey on July 10, 2023 caught 5.44 walleye per gill net at One Pine Lake. Length samples in the latest survey that recorded them ran 6–25 inches. DNR survey details →
One Pine Lake is a 354-acre productive, nutrient-rich eutrophic lake in St. Louis County, Minnesota with a maximum depth of 13 feet. Overall water quality is improving over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 67 other monitored lakes in St. Louis County, One Pine Lake ranks #44 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-15. Methodology: how these readings are compared.
What One Pine Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing13 species recorded
- Ice seasonIce-out around Apr 29
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. One Pine Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether One Pine 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 One Pine Lake
These are the measurements Minnesota PCA publishes for One Pine 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 4.5 ft. Phosphorus 27 µg/L. Chlorophyll-a 8.6 µg/L. TSI 53.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 27µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 8.6µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 53 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about One Pine Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
One Pine Lake typically sits around 51°F at the surface in October. Summer average is about 71°F. Usually warmest in Aug (about 74°F) and coldest in Oct (about 51°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (51°F) to its warmest (74°F).
Typical surface water temperature by month, from 40 field readings (2023–2025) via the EPA Water Quality Portal. See the full One Pine Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for One Pine Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (216,770 cells/mL) on May 30, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Standard Survey on July 10, 2023 caught 5.44 walleye per gill net at One Pine Lake. Length samples in the latest survey that recorded them ran 6–25 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows One Pine Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
10 surveys on file from MN DNR Fisheries. Most recent: 2023-07-10 (Standard Survey).
10 surveys on file · most recent 2023-07-10 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Yellow Perch | 4.34 | 5–10 in 2023-07-10 | 0.16 lb |
| Bluegill | 3.79 | 5–10 in 2023-07-10 | 0.45 lb |
| White Sucker | 3.51 | 8–20 in 2023-07-10 | 2.51 lb |
| Walleye | 3.48 | 6–25 in 2023-07-10 | 1.24 lb |
| Northern Pike | 2.47 | 11–38 in 2023-07-10 | 2.06 lb |
| Black Crappie | 2.25 | 7–11 in 2023-07-10 | 0.44 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.
Yellow Perch
Bluegill
White Sucker
Walleye
From the 2023-07-10 survey
One Pine Lake is a 354-acre lake located seven miles south of Ely. There is a public access with a gravel boat ramp located on the west side of the lake off CSAH 21. One Pine Lake is relatively shallow, with a maximum depth of just 13 feet. Lake bottom substrates along the shoreline are mostly rubble, boulder, and…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for One Pine Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — One PineFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — One Pine (1883)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — One PinePublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
13 ft
Surface area
354 acres
Shoreline
4.6 mi
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
57 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,398 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- One Pine LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near One Pine Lake
Compare lakeside cabins, hotels, and vacation rentals near One Pine 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 One Pine Lake
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Follow One Pine Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing One Pine Lake
Water Quality Trend: Improving
Based on 5 years of monitoring (2020–2025).
Water clarity
Improving5 years
Ice season
Typical ice-out
Apr 29
Earliest Apr 8, 2021 · Latest May 8, 2022
Most recent ice-out
May 8
2022
5 observations · Minnesota PCA ice records
EPA Impairment Status
One Pine 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 MN69-0061-00 · Official waterbody report
Nearby Lakes in St. Louis County
Frequently asked questions about One Pine Lake
Where is One Pine Lake?
- One Pine 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 One Pine Lake?
- One Pine Lake in St. Louis County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.5 ft visibility. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 8.6 µg/L. Maximum depth: 13 ft. Surface area: 353.54 acres.
Is One Pine Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. One Pine Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
What is the water temperature of One Pine Lake?
- One Pine Lake typically sits around 51°F at the surface in October, from 40 EPA Water Quality Portal field readings (2023–2025). That is a typical value for the month, not a live reading.
How deep is One Pine Lake?
- One Pine Lake has a maximum depth of 13 feet. The lake covers 353.54 acres.
What fish are in One Pine Lake?
- Fish species found in One Pine Lake include black bullhead, black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. One Pine Lake is located in St. Louis County, Minnesota.
What did the DNR fisheries survey find at One Pine Lake?
- Minnesota DNR's Standard Survey on July 10, 2023 caught 5.44 walleye per gill net at One Pine Lake. Length samples in the latest survey that recorded them ran 6–25 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows One Pine Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does One Pine Lake thaw?
- One Pine Lake typically has ice-out around Apr 29.
Does One Pine Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for One Pine Lake (clouds, ice, or an off-season gap). The most recent reading was high (216,770 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on One Pine Lake?
- One Pine Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include One Pine Lake. Public access is listed as yes.
Can I fish at One Pine Lake?
- One Pine Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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 One Pine Lake across LakeQuality
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Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in St. Louis County
Species activity outlook by water temperature and season
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Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Lake Superior Basin (MN+WI), ranked by water quality
Lakes in the Rainy Lake Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
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Where this data comes from
49 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA49 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate