Turtle Lake
Polk County, Minnesota525 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Turtle Lake. Here is what has been measured.
- Eutrophic
- 12 ft max depth
- Public access
Turtle Lake in Polk County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 58.5 µg/L. Chlorophyll-a (algae): 25.4 µg/L. Maximum depth: 12 ft. Surface area: 525.13 acres.
Minnesota DNR's Standard Survey on June 17, 1991 caught 11.25 northern pike per gill net at Turtle Lake. DNR survey details →
Turtle Lake is a 525-acre productive, nutrient-rich eutrophic lake in Polk County, Minnesota with a maximum depth of 12 feet. Water clarity is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 18 other monitored lakes in Polk County, Turtle Lake ranks #12 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-23. Methodology: how these readings are compared.
What Turtle Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyAlgae risk
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. Check local advisories before you swim.
Whether Turtle 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 Turtle Lake
These are the measurements Minnesota PCA publishes for Turtle Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 3 ft of visibility. Phosphorus 58.5 µg/L. Chlorophyll-a 25.4 µg/L. TSI 62.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 58.5µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 25.4µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 62 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Turtle Lake
Answers come straight from the public measurements and survey records on this page.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Turtle Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (310,456 cells/mL) on July 19, 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 June 17, 1991 caught 11.25 northern pike per gill net at Turtle Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Turtle Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. 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: 1991-06-17 (Standard Survey).
2 surveys on file · most recent 1991-06-17 (Standard Survey)
35 years old| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 87.16 | 0.52 lb | |
| Walleye | 16.31 | 0.99 lb | |
| Northern Pike | 4.67 | 1.53 lb | |
| Brown Bullhead | 4.25 | 0.86 lb | |
| White Sucker | 2.21 | 2.36 lb | |
| Yellow Perch | 1.88 | 0.62 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.
From the 1991-06-17 survey
FOLLOWING SEVERAL YEARS OF MODERATE WINTER-KILL, TURTLE LAKE'S FISH POPULATION STATUS HAS REVERTED TO ITS ECOLOGICAL CLASSIFICATION-BLH. NOP AND WTS NUMBERS REMAIN STRONG AS WELL. NOP EXHIBIT AN ABOVE AVERAGE GROWTH RATE. CEN AND PERCID SPECIES HAVE BEEN NEARLY ELIMINATED BY LOW DISSOLVED OXYGEN LEVELS DURING WINTER.
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Turtle Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — TurtleFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Turtle (1959)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — TurtleFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — TurtlePublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
12 ft
Surface area
525 acres
Shoreline
6.7 mi
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,289 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Turtle 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 Turtle Lake
Compare lakeside cabins, hotels, and vacation rentals near Turtle Lake in Polk 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Turtle Lake are listed below.
Top-rated places to stay near Turtle 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 →
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Fishing Turtle Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Improving-3.14 µg/L/yr6 years
Chlorophyll-a
Stable-0.68 µg/L/yr6 years
Nearby Lakes in Polk County
Frequently asked questions about Turtle Lake
Where is Turtle Lake?
- Turtle Lake is a lake in Polk County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Turtle Lake?
- Turtle Lake in Polk County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 58.5 µg/L. Chlorophyll-a (algae): 25.4 µg/L. Maximum depth: 12 ft. Surface area: 525.13 acres.
Is Turtle Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Turtle Lake?
- Turtle Lake has a maximum depth of 12 feet. The lake covers 525.13 acres.
What did the DNR fisheries survey find at Turtle Lake?
- Minnesota DNR's Standard Survey on June 17, 1991 caught 11.25 northern pike per gill net at Turtle Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Turtle Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Does Turtle Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Turtle Lake (clouds, ice, or an off-season gap). The most recent reading was high (310,456 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Turtle Lake?
- Turtle Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Turtle Lake. Public access is listed as yes.
Can I fish at Turtle Lake?
- Turtle 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 Turtle Lake across LakeQuality
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Where this data comes from
95 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
MNPCA95 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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory