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South Turtle Lake
Enhanced dataInteractive depth contours
South Turtle LakeVilas County, WI
Contours load with map Access
Interactive depth contours5-foot typical interval · Sonar-derived depth (C-MAP Genesis) · Gaps interpolated · Not for navigation
Source: C-MAP Genesis community sonar (derived)high confidence · QA passed · Select a contour to inspect its mapped depthDepths decoded from C-MAP Genesis Social Map community sonar recordings (used with permission), covering 99% of the lake. Small gaps between recordings are smoothly connected; larger unrecorded areas follow the lake's depth model calibrated to the DNR-documented 40-ft maximum depth. More accurate than a pure model, but still an estimate. Not for navigation.LakeList assistant
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Fishing forecast
Best windows for South Turtle Lake
Weather-based planning built from the National Weather Service hourly forecast near this lake.
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Checking wind, precipitation, and near-term weather windows.
Water temperature
South Turtle Lake water temperature today
Modeled surface-temperature estimate built from seasonal climate, lake depth, and live National Weather Service air temperatures near this lake.
74°FWarm
Seasonal estimate. Checking current National Weather Service air temperatures…
Comfortable summer pattern. Bass and panfish are active; early and late hours beat the midday heat.
Estimates are modeled, not measured. Actual temperatures vary with depth, wind mixing, and recent weather — verify conditions before swimming, boating, or heading onto ice.
Wisconsin DNR water assessment
Impaired waterbody listed
The DNR lists this waterbody as impaired. This notice is not itself a closure; review the official assessment and current guidance before your trip.
303(d) / impairment record
NAPollutants: Mercury, Unknown Pollutant
- Status
- Water Delisted, Pollutant Removed
- Public health
- General Advice
- Recreation
- Full Body Contact
- Aquatic life
- Not specified
Condition has remained stable; water is not impaired.
Review DNR water quality Check consumption advice Source updated 2026-03-18 · LakeList verified 2026-07-12
DNR water check
Water quality quick take
From Wisconsin DNR / Citizen Lake Monitoring readings at South Turtle Lake - Deep Hole.
Sampled Jun 2026Volunteer monitoring since 1991
Somewhat hazy water — summer clarity of 8.7 ft sits near the middle of monitored Wisconsin lakes.
Based on July–August volunteer averages from 2021–2025; each value shows its own year.48Mesotrophic5-yr summer TSI
Moderately clear with moderate nutrients — a typical profile for good swimming lakes.
Water claritySecchi disk depth
8.7 ftJul–Aug 2021 avg (3 readings)
Slight hazeImproving — up ~17% vs earlier years
Clearer than 52% of 596 monitored Wisconsin lakes with current readings.
AlgaeChlorophyll-a
6 µg/LJul–Aug 2025 avg (2 readings)
ModerateWorsening — up ~26% vs earlier years
NutrientsTotal phosphorus — fuels plant & algae growth
38 µg/LLatest single sample · 2025-08-25
Elevated2016–2025
Elevated phosphorus supports strong plant/algae growth pressure.
All readings by year · station details · methodology
Summer averages (July/August)
July/August means; counts in parentheses show how many samples went into each average.
| Year | Secchi | Chlorophyll-a | Total phosphorus |
|---|---|---|---|
| 2025 | — | 6.0 µg/L (2) | 38.0 µg/L (1) |
| 2024 | — | 8.0 µg/L (3) | — |
| 2023 | — | 5.5 µg/L (2) | — |
| 2021 | 8.7 ft (3) | 4.5 µg/L (2) | — |
| 2020 | 7.8 ft (3) | 6.0 µg/L (2) | 20.0 µg/L (1) |
| 2019 | 6.5 ft (3) | 5.0 µg/L (2) | 19.0 µg/L (1) |
| 2018 | 6.1 ft (4) | 11.0 µg/L (2) | — |
| 2017 | 6.1 ft (1) | 9.8 µg/L (4) | — |
| 2016 | — | 17.0 µg/L (2) | 27.0 µg/L (1) |
| 2015 | 7.4 ft (4) | 15.0 µg/L (2) | — |
Latest individual samples: Secchi 9 ft (2021-08-19), chlorophyll-a 2 µg/L (2026-06-27), and total phosphorus 38 µg/L (2025-08-25).
Secchi clarity is how deep a black-and-white disk stays visible from the surface — more feet means clearer water.
Chlorophyll-a is an algae pigment; higher values signal more algae in the water column.
Total phosphorus is a nutrient that feeds algae and aquatic plants. It is not a weed survey — depth, bottom type, water movement, and management change the actual lake experience.
South Turtle Lake - Deep HoleStation 643257 · TSI based on chlorophyll
Modeled from DNR/CLMN monitoring — not a safety or swim-condition report. Verify current conditions locally. LakeList verified 2026-07-12.Official Wisconsin information
Plan with DNR sources
LakeList links to the authoritative record so you can verify maps, rules, and current notices before leaving.
Historical DNR depth maps1 converted map sheetView DNR depth mapHistorical map · not for navigationFishing regulationsVerify current seasons, limits, and restrictionsOfficial DNR lake pageFacts, advisories, boating, and water qualityWater quality reportsMonitoring stations, clarity, and DNR reportsInvasive speciesVerified, observed, and historical AIS recordsBoating ordinancesLocal slow-no-wake and water-use restrictionsFish consumption advisoriesStatewide and waterbody-specific health guidance
Historical depth maps are not for navigation. Verify regulations and access at the official source before your trip.
Historical Wisconsin DNR maps
South Turtle Lake depth maps
1 converted map sheet. These historical surveys are not for navigation.
Navigable depth map
South Turtle Lake · sheet 1
Pan, zoom, and inspect the converted Wisconsin DNR historical map image in the browser. Historical survey — not for navigation.
Source: Wisconsin DNR · WBIC 2310200 · image navigation only; spatial alignment pending · Historical lake maps are not for navigation.
Source: Wisconsin Department of Natural Resources. Converted for browser access with source URLs, checksums, and retrieval dates retained. Historical lake maps are not for navigation.
Wisconsin DNR fisheries survey
Fish population survey
Structured LakeList extraction from the 2026 DNR fisheries survey. Population estimates, density, and catch-rate indices use different units, methods, and scopes, so each value is presented in its original form rather than normalized against a different measure.
Survey indicatorsValues keep their source unit and method; unlike measures are not scaled or compared.
Management contextSouth Turtle Lake bass-and-panfish electrofishing results. Panfish and nongame metrics apply to three 0.5-mile all-species stations; bass and other gamefish use the full 6.75 shocked miles. Walleye, pike and muskellunge remain bycatch-scoped because they were not survey targets.
Wisconsin DNR's 2026 survey found moderate-high largemouth-bass catch, moderate smallmouth-bass catch, very high bluegill and pumpkinseed indices, a 40-fish rock-bass sample, 22 yellow perch and 178 incidentally captured walleye.
- Largemouth-bass catch ranked between the 50th and 75th lake-class percentiles; bluegill and pumpkinseed catch ranked above the 90th percentile.
- The printed smallmouth-bass CPUE of 4.23 fish per mile conflicts with 25 fish across 6.75 reported miles, so that CPUE was excluded rather than corrected or guessed.
- Do not convert walleye or other bycatch counts into population estimates; the report says those species were not specifically targeted.
Black crappie
3 fishIncidental catch count · p. 5
Bluegill
378 fishTotal captured · p. 2252 fish/mileElectrofishing CPUE · p. 2237 fishCaptured fish at least 3 inches · p. 25.5 inchesAverage length for fish at least 3 inches · p. 2
Bluntnose minnow
3 fishIncidental catch count · p. 5
Golden shiner
1 fishIncidental catch count · p. 5
Greater redhorse
1 fishIncidental catch count · p. 5
Johnny darter
1 fishIncidental catch count · p. 5
Largemouth bass
59 fishTotal captured · p. 125 percentShare at least 14 inches long · p. 111.3 inchesAverage captured length · p. 117.4 inchesMaximum captured length · p. 1
Mimic shiner
3 fishIncidental catch count · p. 5
Mottled sculpin
4 fishIncidental catch count · p. 5
Muskellunge
1 fishIncidental catch count · p. 5
Northern pike
9 fishIncidental catch count · p. 5
Pumpkinseed
32 fishTotal captured · p. 321.3 fish/mileElectrofishing CPUE · p. 34.9 inchesAverage captured length · p. 37 inchesMaximum captured length · p. 3
Rock bass
40 fishTotal captured · p. 326.7 fish/mileElectrofishing CPUE · p. 36.5 inchesAverage captured length · p. 39.7 inchesMaximum captured length · p. 3
Shorthead redhorse
3 fishIncidental catch count · p. 5
Silver redhorse
1 fishIncidental catch count · p. 5
Smallmouth bass
25 fishTotal captured · p. 236 percentShare at least 14 inches long · p. 212.4 inchesAverage captured length · p. 216.4 inchesMaximum captured length · p. 2
Tiger muskellunge
3 fishIncidental catch count · p. 5
Walleye
178 fishIncidental catch count · p. 44.7 inchesMinimum bycatch length · p. 424 inchesMaximum bycatch length · p. 48.2 inchesAverage bycatch length · p. 4
White sucker
4 fishIncidental catch count · p. 5
Yellow perch
22 fishTotal captured · p. 42.6 inchesMinimum captured length · p. 410.2 inchesMaximum captured length · p. 45.4 inchesAverage captured length · p. 4
2026 Fisheries Information Sheet: South Turtle Lake, Vilas CountyMatched by exact wbic and name county · WBICs 2310200 · verified 2026-07-18Wisconsin DNR fisheries survey report; LakeList operator documented permission to leverage this report with source attribution.
466surface acres
40max depth feet
1public access points
46.2134, -89.8948latitude, longitude
Access
Public access points
Boat launchSouth Turtle Lake Access46.21769, -89.89095Managed by TOWNSHIPTOWN OF WINCHESTERRamp surface: PavedADA-accessible feature: NoVerified 2026-07-12
Nearby
Trip-planning places
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Fishery
Notable species
MuskyPanfishWalleyeLargemouth BassNorthern PikeSmallmouth Bass
Depth FAQ
How deep is South Turtle Lake?
South Turtle Lake is 40 feet deep at its deepest point, according to Wisconsin DNR records.
Is there a free depth map of South Turtle Lake?
Yes. LakeList publishes a free interactive depth contour map of South Turtle Lake at a typical 5-foot interval, with an optional 3D underwater view, derived from C-MAP Genesis community sonar (derived) survey data.
Where does the South Turtle Lake depth map come from?
The interactive depth contours are derived from C-MAP Genesis community sonar (derived). Each contour set passes a visual QA review against the source document before it is published. The depths are derived from community sonar recordings (C-MAP Genesis Social Map, used with permission), with gaps between recordings interpolated; not for navigation.
Trust and freshness
Where this lake data comes from
Wisconsin DNR Lake Mapsname, coordinates, county, source identifiers
LakeList record updated 2026-07-14
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