Oak Lake
Pine County, Minnesota459 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Oak Lake. Here is what has been measured.
- Impaired · Impaired biota (cause unknown)
- 20 ft max depth
- Public access
- Limited data
Oak Lake in Pine County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Maximum depth: 20 ft. Surface area: 458.74 acres.
Minnesota DNR's Standard Survey on August 14, 2023 caught 0.67 walleye per gill net at Oak Lake. DNR survey details →
Oak Lake is a 459-acre lake in Pine County, Minnesota with a maximum depth of 20 feet (8-foot average). Overall water quality is improving over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-08. Methodology: how these readings are compared.
What Oak Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing12 species recorded
- Ice seasonIce-out around Apr 14
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Oak Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Oak 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 Oak Lake
These are the measurements Minnesota PCA publishes for Oak 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 ft. TSI 57.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4ft | 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. | 57 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Oak Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Oak Lake typically sits around 64°F at the surface in September. Summer average is about 72°F. Usually warmest in Jul (about 74°F) and coldest in May (about 53°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (53°F) to its warmest (74°F).
Typical surface water temperature by month, from 26 field readings (2011–2025) via the EPA Water Quality Portal. See the full Oak Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Oak Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (42,462 cells/mL) on July 7, 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 August 14, 2023 caught 0.67 walleye per gill net at Oak Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Oak Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
11 surveys on file from MN DNR Fisheries. Most recent: 2023-08-14 (Standard Survey).
11 surveys on file · most recent 2023-08-14 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 19.59 | 7–12 in 2023-08-14 | 0.67 lb |
| Yellow Perch | 10.64 | 4–7 in 2023-08-14 | 0.17 lb |
| Black Crappie | 8.78 | 4–12 in 2023-08-14 | 0.31 lb |
| Bluegill | 7.98 | 3–8 in 2023-08-14 | 0.23 lb |
| Largemouth Bass | 7.05 | 9–18 in 2023-08-14 | 1.76 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.
Black Bullhead
Yellow Perch
Black Crappie
Bluegill
From the 2023-08-14 survey
Oak Lake is a 422 acre lake in northern Pine County. A paved public access and a private resort are both located on the south shore of the lake. Water clarity is good despite sporadic algae blooms in August. Oak Lake is managed primarily for Walleye. Walleye fry have been stocked in odd years since 2017. Lake use is…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Oak Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OakFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Oak (0359)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — OakFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — OakPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
20 ft
Average depth
8 ft
Surface area
459 acres
Shoreline
4.8 mi
Littoral zone
94%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
37 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,106 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Oak 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 Oak Lake
Compare lakeside cabins, hotels, and vacation rentals near Oak Lake in Pine 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 Oak Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Follow Oak Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Oak Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Ice season
Typical ice-out
Apr 14
Earliest Apr 11, 2006 · Latest Apr 25, 2008
Most recent ice-out
Apr 25
2008
4 observations · Minnesota PCA ice records
EPA Impairment Status
Oak 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: Aquatic life, Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN58-0048-00 · Official waterbody report
Nearby Lakes in Pine County
Frequently asked questions about Oak Lake
Where is Oak Lake?
- Oak Lake is a lake in Pine County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Oak Lake?
- Oak Lake in Pine County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Maximum depth: 20 ft. Surface area: 458.74 acres.
Is Oak Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Oak Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Oak Lake?
- Oak Lake typically sits around 64°F at the surface in September, from 26 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Oak Lake?
- Oak Lake has a maximum depth of 20 feet and an average depth of 8 feet. The lake covers 458.74 acres.
What fish are in Oak Lake?
- Fish species found in Oak Lake include black bullhead, black crappie, bluegill, brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Oak Lake is located in Pine County, Minnesota.
What did the DNR fisheries survey find at Oak Lake?
- Minnesota DNR's Standard Survey on August 14, 2023 caught 0.67 walleye per gill net at Oak Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Oak Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Oak Lake thaw?
- Oak Lake typically has ice-out around Apr 14.
Does Oak Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Oak Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (42,462 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Oak Lake?
- Oak Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Oak Lake. Public access is listed as yes.
Can I fish at Oak Lake?
- Oak 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 Oak 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 Pine County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the St. Croix Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
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State Parks Near Oak Lake
Other Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
33 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
MNPCA33 samples · 2020–2025
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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate