Turtle Lake
Beltrami County, Minnesota1,607 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Turtle Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
- 45 ft max depth
- Public access
Turtle Lake in Beltrami County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 4.9 µg/L. Maximum depth: 45 ft. Surface area: 1606.58 acres.
Minnesota DNR's Standard Survey on August 2, 2021 caught 5.00 walleye per gill net at Turtle Lake. DNR survey details →
Free interactive depth-contour map of Turtle Lake, reaching a maximum surveyed depth of 45 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Turtle Lake is a 1,607-acre mesotrophic lake in Beltrami County, Minnesota with a maximum depth of 45 feet. Overall water quality is improving over recent sampling years. The lake supports 16 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available with 1 public boat landing. Compared to the 84 other monitored lakes in Beltrami County, Turtle Lake ranks #17 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.
- Clear water10.2 ft of visibility
- Boat launch1 documented ramp
- Fishing16 species recorded
- Ice seasonIce-out around Apr 23
- Deep water45 ft surveyed max depth
- Big water1,607 acres
Swimming conditions
Readings onlyLow algae
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. Turtle Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. 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.
Good clarity, visible to about 10.2 ft. Phosphorus 15 µg/L. Chlorophyll-a 4.9 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 15µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 4.9µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Turtle Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Turtle Lake typically sits around 63°F at the surface in September. Summer average is about 71°F. Usually warmest in Jul (about 76°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (58°F) to its warmest (76°F).
Typical surface water temperature by month, from 64 field readings (2016–2025) via the EPA Water Quality Portal. See the full Turtle Lake water temperature breakdown →
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 moderate (94,624 cells/mL) on May 20, 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 2, 2021 caught 5.00 walleye 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 improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2025-08-06 (Targeted Survey).
13 surveys on file · most recent 2025-08-06 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Yellow Perch | 35.17 | 3–10 in 2021-08-02 | 0.13 lb |
| Bluntnose Minnow | 26.04 |
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
From the 2025-08-06 survey
Temperature and dissolved oxygen (DO) measurements were collected from the deepest basin in Turtle Lake on August 6th, 2025, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee, the most sensitive coldwater species present in this lake.…
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 (1737)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
45 ft
Surface area
1,607 acres
Shoreline
11.4 mi
Littoral zone
45%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
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 Beltrami 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 Turtle Lake
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Follow Turtle Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Turtle Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Stable6 years
Phosphorus
Improving-0.4 µg/L/yr6 years
Chlorophyll-a
Improving-0.33 µg/L/yr6 years
Ice season
Typical ice-out
Apr 23
Earliest Mar 25, 2012 · Latest May 14, 2013
Typical ice-in
Nov 21
Earliest Nov 4, 1991 · Latest Dec 11, 1999
Most recent ice-out
May 4
2023
120 observations · Minnesota PCA ice records
EPA Impairment Status
Turtle 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 MN04-0159-00 · Official waterbody report
Nearby Lakes in Beltrami County
Frequently asked questions about Turtle Lake
Where is Turtle Lake?
- Turtle Lake is a lake in Beltrami 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 Beltrami County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.2 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 4.9 µg/L. Maximum depth: 45 ft. Surface area: 1606.58 acres.
Is Turtle Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Turtle Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Turtle Lake?
- Turtle Lake typically sits around 63°F at the surface in September, from 64 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Turtle Lake?
- Turtle Lake has a maximum depth of 45 feet. The lake covers 1606.58 acres.
What fish are in Turtle Lake?
- Fish species found in Turtle Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, hybrid sunfish, largemouth bass, northern pike, northern sunfish, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Turtle Lake is located in Beltrami County, Minnesota.
What did the DNR fisheries survey find at Turtle Lake?
- Minnesota DNR's Standard Survey on August 2, 2021 caught 5.00 walleye 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 improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Turtle Lake thaw?
- Turtle Lake typically has ice-out around Apr 23. Ice typically forms around Nov 21. The open water season is approximately 212 days.
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 moderate (94,624 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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Compare Turtle Lake With Nearby Lakes
Beltrami County · 6.5 ft
Beltrami County · 14 ft
Beltrami County · 11.8 ft
Beltrami County · 11.2 ft
Beltrami County · 9.7 ft
Beltrami County · 9.2 ft
Where this data comes from
84 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
MNPCA84 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 (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
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate