North Turtle Lake
Otter Tail County, Minnesota1,773 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for North Turtle Lake. Here is what has been measured.
- Eutrophic
- 19 ft max depth
- Public access
North Turtle Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Phosphorus: 54.5 µg/L. Chlorophyll-a (algae): 22 µg/L. Maximum depth: 19 ft. Surface area: 1773.16 acres.
Minnesota DNR's Targeted Survey on May 22, 2024 caught 80.83 largemouth bass per hour of electrofishing at North Turtle Lake. Length samples in the latest survey that recorded them ran 2–18 inches. DNR survey details →
Free interactive depth-contour map of North Turtle Lake, reaching a maximum surveyed depth of 15 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
North Turtle Lake is a 1,773-acre productive, nutrient-rich eutrophic lake in Otter Tail County, Minnesota with a maximum depth of 19 feet. 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. Compared to the 65 other monitored lakes in Otter Tail County, North Turtle Lake ranks #64 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-10. Methodology: how these readings are compared.
North Turtle Lake covers about 1,800 acres in Otter Tail County. The median ice-out date is April 16, which is when the open-water season begins. If you are planning to stay, you can search lake houses and cabins around North Turtle Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What North Turtle Lake is good for
From access and monitoring records, not editorial picks.
- Fishing12 species recorded
- Ice seasonIce-out around Apr 16
- Big water1,773 acres
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 North 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 North Turtle Lake
These are the measurements Minnesota PCA publishes for North Turtle 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. Phosphorus 54.5 µg/L. Chlorophyll-a 22 µg/L. TSI 60.
| 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 | 54.5µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 22µg/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. | 60 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about North Turtle Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Targeted Survey on May 22, 2024 caught 80.83 largemouth bass per hour of electrofishing at North Turtle Lake. Length samples in the latest survey that recorded them ran 2–18 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows North Turtle Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2025-04-17 (Targeted Survey).
9 surveys on file · most recent 2025-04-17 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 27.03 | 6–13 in 2020-08-17 | 0.78 lb |
| Bluegill | 26.78 | 3–7 in 2020-08-17 | 0.15 lb |
| Largemouth Bass | 24.49 | 2–18 in 2024-05-22 | 1.83 lb |
| Yellow Perch | 21.04 | 5–10 in 2020-08-17 | 0.13 lb |
| Yellow Bullhead | 19.14 | 5–16 in 2020-08-17 | 0.52 lb |
| Black Crappie | 9.60 | 5–13 in 2025-04-17 | 0.33 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
Bluegill
Largemouth Bass
Yellow Perch
From the 2025-04-17 survey
North Turtle Lake is a 1,484-acre eutrophic (fertile) lake located in central Otter Tail County immediately northeast of Underwood, MN. North Turtle Lake is part of the Otter Tail River Watershed. There are no navigable inlets or outlets. The immediate watershed is composed primarily of agricultural land interspersed…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for North Turtle Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — North TurtleFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — North TurtleFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — North TurtlePublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
19 ft
Surface area
1,773 acres
Shoreline
22.9 mi
Littoral zone
82%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
5 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,322 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near North Turtle Lake
Compare lakeside cabins, hotels, and vacation rentals near North Turtle Lake in Otter Tail 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 North Turtle Lake are listed below.
Top-rated places to stay near North 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 →
Follow North Turtle Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing North Turtle Lake
- → North Turtle Lake fishing: DNR survey catch rates, species & stocking
- → North Turtle Lake fishing forecast & best times (species outlook + 14-day solunar calendar)
- → North Turtle Lake fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from North Turtle Lake? (mercury & PFAS guide)
Water Quality Trend: Improving
Based on 5 years of monitoring (2020–2025).
Water clarity
Stable5 years
Phosphorus
Improving-10.61 µg/L/yr4 years
Chlorophyll-a
Improving-4.34 µg/L/yr4 years
Ice season
Typical ice-out
Apr 16
Earliest Mar 29, 2021 · Latest Apr 30, 2023
Most recent ice-out
Apr 30
2023
5 observations · Minnesota PCA ice records
Nearby Lakes in Otter Tail County
Frequently asked questions about North Turtle Lake
Where is North Turtle Lake?
- North Turtle Lake is a lake in Otter Tail County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of North Turtle Lake?
- North Turtle Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Phosphorus: 54.5 µg/L. Chlorophyll-a (algae): 22 µg/L. Maximum depth: 19 ft. Surface area: 1773.16 acres.
Is North Turtle Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is North Turtle Lake?
- North Turtle Lake has a maximum depth of 19 feet. The lake covers 1773.16 acres.
What fish are in North Turtle Lake?
- Fish species found in North Turtle Lake include black bullhead, black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead, yellow perch. North Turtle Lake is located in Otter Tail County, Minnesota.
What did the DNR fisheries survey find at North Turtle Lake?
- Minnesota DNR's Targeted Survey on May 22, 2024 caught 80.83 largemouth bass per hour of electrofishing at North Turtle Lake. Length samples in the latest survey that recorded them ran 2–18 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows North Turtle Lake’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does North Turtle Lake thaw?
- North Turtle Lake typically has ice-out around Apr 16.
Can I fish at North Turtle Lake?
- Public access to North Turtle Lake is listed as yes on the lake record. 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 North Turtle Lake across LakeQuality
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Where this data comes from
80 measurements from 2 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
MNPCA80 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 (2)
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
Ice data from Minnesota DNR Climate