Turtle Lake Inlet
Cook County, MinnesotaView mapDirections
No nutrient or algae sampling on record from Minnesota PCA for this lake.
- Limited data
Turtle Lake Inlet in Cook County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported.
Turtle Lake Inlet is a lake in Cook County, Minnesota. Water clarity is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-07-22. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Turtle Lake Inlet 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 Inlet
These are the measurements Minnesota PCA publishes for Turtle Lake Inlet, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data.
Ask about Turtle Lake Inlet
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Turtle Lake Inlet typically sits around 62°F at the surface in September. Summer average is about 72°F. Usually warmest in Aug (about 75°F) and coldest in May (about 51°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (51°F) to its warmest (75°F).
Typical surface water temperature by month, from 69 field readings (2011–2025) via the EPA Water Quality Portal. See the full Turtle Lake Inlet water temperature breakdown →
Stays via Stay22
Stays near Turtle Lake Inlet
Compare lakeside cabins, hotels, and vacation rentals near Turtle Lake Inlet in Cook 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 Inlet
Prices for Oct 16–18, 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 Turtle Lake Inlet’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Turtle Lake Inlet
Water Quality Trend: Stable
Based on 5 years of monitoring (2020–2025).
Water clarity
Worsening4 years
Phosphorus
Improving-2.49 µg/L/yr4 years
Chlorophyll-a
Stable-0.03 µg/L/yr4 years
Nearby Lakes in Cook County
Frequently asked questions about Turtle Lake Inlet
Where is Turtle Lake Inlet?
- Turtle Lake Inlet is a lake in Cook 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 Inlet?
- Turtle Lake Inlet in Cook County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported.
Is Turtle Lake Inlet safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Turtle Lake Inlet?
- Turtle Lake Inlet typically sits around 62°F at the surface in September, from 69 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
Explore Turtle Lake Inlet across LakeQuality
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Cook County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Lake Superior Basin (MN+WI), ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Turtle Lake Inlet
Other Lakes in Minnesota
Where this data comes from
4 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Grand Portage Reservation
GPC5_WQX4 samples · 2021–2025
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.