Turtle Lake
Turtle Lake in Polk County, Minnesota has a water quality grade of D (Nutrient-rich). 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.
- Clarity
- 3 ft
- Max depth
- 12 ft
- Area
- 525 acres
- Type
- Eutrophic
- Trend
- → Stable
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Turtle Lake →
Next lake in Polk County
Turtle Lake is a 525-acre productive, nutrient-rich eutrophic lake in Polk County, Minnesota with a maximum depth of 12 feet. Water quality is graded D based on 2 sampling years through 2025. 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. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 3 ft of visibility. Phosphorus level: 58.5 µg/L. Chlorophyll-a: 25.4 µg/L. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | Not graded |
| Phosphorus | 58.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 25.4 µg/L | Poor |
| Trophic State Index (TSI) | 62 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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 grade measures nutrients and algae, not lodging — cabins and rentals around Turtle Lake are listed below.
Top-rated places to stay near Turtle Lake
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 →
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 ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 12 ft |
| Surface Area | 525 acres |
| Shoreline Length | 6.7 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Turtle LakePublic
Fishing Turtle Lake
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 1991-06-17 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | 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, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
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
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.043 m/yr | 6 |
| Phosphorus | ↑ Improving | -3.14 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | -0.68 µg/L/yr | 6 |
County Ranking
Ranked #12 of 19 lakes in Polk County
Nearby Lakes With Higher Grades
Turtle Lake holds Grade D. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Polk County
Frequently asked questions about Turtle Lake
What is the water quality grade for Turtle Lake?
- Turtle Lake in Polk County, Minnesota has a water quality grade of D (Nutrient-rich). 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?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Turtle Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 25.4 µg/L. Always check local health department advisories before swimming.
How deep is Turtle Lake?
- Turtle Lake has a maximum depth of 12 feet. The lake covers 525.13 acres.
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.
Explore Turtle Lake across LakeGrade
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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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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