Big Lake
Vilas County, Wisconsin780 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Big Lake. Here is what has been measured.
- Mesotrophic
- Rusty Crayfish
- 30 ft max depth
- Limited data
Big Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Phosphorus: 17.4 µg/L. Maximum depth: 30 ft. Surface area: 780 acres.
Wisconsin DNR rates Walleye as abundant on Big Lake. DNR survey details →
Big Lake is a 780-acre mesotrophic lake in Vilas County, Wisconsin with a maximum depth of 30 feet. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Compared to the 102 other monitored lakes in Vilas County, Big Lake ranks #23 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-09-10. Methodology: how these readings are compared.
What Big Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
- Deep water30 ft surveyed max depth
Swimming conditions
Readings onlyLimited data
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.
No clarity data. Phosphorus 17.4 µg/L. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 17.4µg/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. | 45 | 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 (366,438 cells/mL) on April 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR rates Walleye as abundant on Big Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Lake’s water-quality measurements separately, and the water-quality trend over 4 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. 4 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
30 ft
Surface area
780 acres
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Stays near Big Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Big 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 4 years of monitoring (2021–2025).
Water clarity
Improving3 years
Phosphorus
Improving-2.45 µg/L/yr4 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. Phosphorus: 17.4 µg/L. Maximum depth: 30 ft. Surface area: 780 acres.
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?
- Big Lake has a maximum depth of 30 feet. The lake covers 780 acres.
What fish are in Big Lake?
- Fish species found in Big Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Big Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Big Lake?
- Wisconsin DNR rates Walleye as abundant on Big Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Lake’s water-quality measurements separately, and the water-quality trend over 4 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
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 (366,438 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Explore Big Lake across LakeQuality
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Where this data comes from
3 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX3 samples · 2025
Analytical methods
- Phosphorus by Colorimetry
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.
Other records on this page
Fish and recreation data from Wisconsin DNR Lakes