Big Lake
Vilas County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Big Lake. Here is what has been measured.
- Mesotrophic
- 76 ft max depth
- Public access
Big Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 12.5 ft visibility. Phosphorus: 12.9 µg/L.
Big Lake is a mesotrophic lake in Vilas County, Wisconsin with an estimated average depth of about 76 feet. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 102 other monitored lakes in Vilas County, Big Lake ranks #22 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-27. Methodology: how these readings are compared.
What Big Lake is good for
From access and monitoring records, not editorial picks.
- Clear water12.5 ft of visibility
- Boat launch2 documented ramps
Swimming conditions
Readings onlyLow algae
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 Big Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Big Lake
These are the measurements Wisconsin DNR publishes for Big Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 12.5 ft. Phosphorus 12.9 µg/L. TSI 41.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 12.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12.9µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 41 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Big Lake
Answers come straight from the public measurements and survey records on this page.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Big Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (164,437 cells/mL) on May 23, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
Max depth
~76 ft est.
Public access
Yes
Listed by Wisconsin DNR
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wisconsin has not published bathymetry for Big Lake.
Lake Size & Watershed
Watershed (drainage) area
12 sq mi
HydroLAKES / HydroSHEDS
Surface area
788 acres
HydroLAKES / HydroSHEDS
Shoreline
9 mi
HydroLAKES / HydroSHEDS
Elevation
1,608 ft
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
- Big Lake - Hwy KPublic
- Rice CreekPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Big Lake
Compare lakeside cabins, hotels, and vacation rentals near Big 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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Follow Big Lake’s readings
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Fishing Big Lake
Water Quality Trend: Stable
Based on 7 years of monitoring (2020–2026).
Water clarity
Stable7 years
Phosphorus
Stable+0.01 µg/L/yr6 years
Nearby Lakes in Vilas County
Frequently asked questions about Big Lake
Where is Big Lake?
- Big Lake is a lake in Vilas County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Big Lake?
- Big Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 12.5 ft visibility. Phosphorus: 12.9 µg/L.
Is Big Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Big Lake?
- No published bathymetric survey covers Big Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 76 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Does Big Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Big Lake (clouds, ice, or an off-season gap). The most recent reading was high (164,437 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Big Lake?
- Big Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Big Lake - Hwy K, Rice Creek. Public access is listed as yes.
Can I fish at Big Lake?
- Big Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Big Lake across LakeQuality
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Where this data comes from
40 measurements from 3 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_WQX40 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (3)
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)
Named boat-access points from the USGS National Boat Ramps inventory