Turtle Lake
Turtle Lake in Beltrami County, Minnesota has a water quality grade of A (Excellent). 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.
- Clarity
- 10.2 ft
- Typical in August
- 67°F
- Max depth
- 45 ft
- Area
- 1,607 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 23
- Open water
- 212 days
Next lake in Beltrami County
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. Water quality is graded A based on 2 sampling years through 2025. 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. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Good clarity, visible to about 10.2 ft. Phosphorus level: 15 µg/L. Chlorophyll-a: 4.9 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.2 ft | Not graded |
| Phosphorus | 15 µg/L | Good |
| Chlorophyll-a (Algae) | 4.9 µg/L | Good |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay 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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Water Temperature
Turtle Lake typically sits around 67°F at the surface in August. 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.
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 ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 45 ft |
| Surface Area | 1,607 acres |
| Shoreline Length | 11.4 mi |
| Littoral Zone | 45% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Turtle LakePublic
Fish Species
Click a species to see every graded 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.
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2025-08-06 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| CNM | 43.03 | — |
| Yellow Perch | 35.17 | 0.13 lb |
| Bluntnose Minnow | 26.04 | — |
| MMS | 24.08 | — |
| IOD | 13.49 | — |
| MTS | 12.94 | — |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
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
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.039 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.4 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.33 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (120 observations).
Estimated open water season: 212 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-25 (2012) | 2013-05-14 (2013) |
| Ice-In | 1991-11-04 (1991) | 1999-12-11 (1999) |
Most recent ice-out: 2023-05-04
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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN04-0159-00 · Official waterbody report
County Ranking
Ranked #17 of 85 lakes in Beltrami County
Nearby Lakes in Beltrami County
Frequently asked questions about Turtle Lake
What is the water quality grade for Turtle Lake?
- Turtle Lake in Beltrami County, Minnesota has a water quality grade of A (Excellent). 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?
- Excellent for swimming, crystal clear water with minimal algae. Turtle Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 4.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Turtle Lake?
- Turtle Lake typically sits around 67°F at the surface in August, 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.
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.
Explore Turtle Lake across LakeGrade
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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)
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
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