Gunlock Lake
Gunlock Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Water clarity: 9 ft visibility. Phosphorus: 18.9 µg/L.
- Clarity
- 9 ft
- Typical in August
- 72°F
- Max depth
- ~54 ft est.
- Type
- Mesotrophic
- Trend
- ↓ Declining
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Gunlock Lake is a mesotrophic lake in Vilas County, Wisconsin with an estimated average depth of about 54 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is declining over recent sampling years. Public access is available with 1 public boat landing. Compared to the 102 other monitored lakes in Vilas County, Gunlock Lake ranks #57 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-19. 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 9 ft. Phosphorus level: 18.9 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | Not graded |
| Phosphorus | 18.9 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Gunlock Lake
Compare lakeside cabins, hotels, and vacation rentals near Gunlock 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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Water Temperature
Gunlock Lake typically sits around 72°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 75°F) and coldest in Apr (about 50°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 17 field readings (2024–2026) via the EPA Water Quality Portal. See the full Gunlock Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~54 ft est. |
| Average Depth | ~13 ft est. |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wisconsin has not published bathymetry for Gunlock Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Gunlock LakeSemi-private
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Gunlock Lake
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.339 m/yr | 7 |
| Phosphorus | → Stable | -0.16 µg/L/yr | 7 |
County Ranking
Ranked #57 of 103 lakes in Vilas County
Nearby Lakes in Vilas County
Frequently asked questions about Gunlock Lake
Where is Gunlock Lake?
- Gunlock 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 Gunlock Lake?
- Gunlock Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Water clarity: 9 ft visibility. Phosphorus: 18.9 µg/L.
Is Gunlock Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Gunlock Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Gunlock Lake?
- Gunlock Lake typically sits around 72°F at the surface in August, from 17 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Gunlock Lake?
- No published bathymetric survey covers Gunlock Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 54 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Gunlock Lake?
- Gunlock Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Gunlock Lake.
Explore Gunlock Lake across LakeQuality
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Moderate nutrients, good water quality
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Where this data comes from
76 measurements from 2 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX76 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
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)
Named boat-access points from the USGS National Boat Ramps inventory