South Turtle Lake
South Turtle Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Water clarity: 8 ft visibility. Phosphorus: 17.3 µg/L. Maximum depth: 40 ft. Surface area: 466 acres.
Wisconsin DNR lists Musky as common on South Turtle Lake. DNR survey details →
- Clarity
- 8 ft
- Max depth
- 40 ft
- Area
- 466 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
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South Turtle Lake is a 466-acre mesotrophic lake in Vilas County, Wisconsin with a maximum depth of 40 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 102 other monitored lakes in Vilas County, South Turtle Lake ranks #56 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-27. Grade methodology: LakeQuality 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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 8 ft. Phosphorus level: 17.3 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8 ft | Not graded |
| Phosphorus | 17.3 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near South Turtle Lake
Compare lakeside cabins, hotels, and vacation rentals near South Turtle Lake in Vilas County, Wisconsin — 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.
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Wisconsin DNR lists Musky as common on South Turtle Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades South Turtle Lake B from EPA Water Quality Portal chemistry, 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.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1991. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 40 ft |
| Surface Area | 466 acres |
| Public Access | Yes |
Recreation & Access
- South Turtle LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing South 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 data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.75 m/yr | 2 |
| Phosphorus | ↑ Improving | -1.3 µg/L/yr | 6 |
County Ranking
Ranked #56 of 103 lakes in Vilas County
Nearby Lakes in Vilas County
Frequently asked questions about South Turtle Lake
Where is South Turtle Lake?
- South Turtle Lake is a lake in Vilas County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for South Turtle Lake?
- South Turtle Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Water clarity: 8 ft visibility. Phosphorus: 17.3 µg/L. Maximum depth: 40 ft. Surface area: 466 acres.
Is South Turtle Lake safe to swim in?
- Good for swimming, clear water with low algae levels. South Turtle Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is South Turtle Lake?
- South Turtle Lake has a maximum depth of 40 feet. The lake covers 466 acres.
What fish are in South Turtle Lake?
- Fish species found in South Turtle Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. South Turtle Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at South Turtle Lake?
- Wisconsin DNR lists Musky as common on South Turtle Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades South Turtle Lake B from EPA Water Quality Portal chemistry, 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.
Are there boat ramps on South Turtle Lake?
- South Turtle Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include South Turtle Lake. Public access is listed as yes.
Explore South Turtle Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Vilas County
Species activity outlook by water temperature and season
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Where to stay at Wisconsin's top lakes, each with its grade
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Moderate nutrients, good water quality
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Where this data comes from
25 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX25 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
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)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory