Black Oak Lake
Black Oak Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Water clarity: 29 ft visibility. Phosphorus: 10.6 µg/L. Maximum depth: 85 ft. Surface area: 564 acres.
Wisconsin DNR rates Panfish as abundant on Black Oak Lake. DNR survey details →
- Clarity
- 29 ft
- Typical in August
- 72°F
- Max depth
- 85 ft
- Area
- 564 acres
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
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Black Oak Lake is a 564-acre cold, clear oligotrophic lake in Vilas County, Wisconsin with a maximum depth of 85 feet. Water quality is graded B based on 1 sampling years through 2026. Water clarity is improving over recent sampling years. The lake supports 6 documented fish species including Panfish, Largemouth Bass, and Smallmouth Bass. Public access is available with 1 public boat landing. Compared to the 102 other monitored lakes in Vilas County, Black Oak Lake ranks #41 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)
Crystal clear, you can see 29 ft down. Phosphorus level: 10.6 µg/L. Trophic State Index: 33.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 29 ft | Not graded |
| Phosphorus | 10.6 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 33 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Black Oak Lake
Compare lakeside cabins, hotels, and vacation rentals near Black Oak 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.
Top-rated places to stay near Black Oak Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
Black Oak Lake typically sits around 72°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in Jun (about 69°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 8 field readings (2024–2025) via the EPA Water Quality Portal. See the full Black Oak Lake water temperature breakdown →
Wisconsin DNR rates Panfish as abundant on Black Oak Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Black Oak Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 7 years of monitoring is stable. 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 2002. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 85 ft |
| Surface Area | 564 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Black Oak 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 Black Oak 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.
Source: USGS Nonindigenous Aquatic Species (NAS) Database. Hover a chip to see scientific name, ecological context, status, and first-observed year.
Water Quality Trend: → Stable
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.563 m/yr | 7 |
| Phosphorus | ↓ Declining | +2.49 µg/L/yr | 6 |
County Ranking
Ranked #41 of 103 lakes in Vilas County
Nearby Lakes in Vilas County
Frequently asked questions about Black Oak Lake
Where is Black Oak Lake?
- Black Oak 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 Black Oak Lake?
- Black Oak Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Water clarity: 29 ft visibility. Phosphorus: 10.6 µg/L. Maximum depth: 85 ft. Surface area: 564 acres.
Is Black Oak Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Black Oak Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Black Oak Lake?
- Black Oak Lake typically sits around 72°F at the surface in August, from 8 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Black Oak Lake?
- Black Oak Lake has a maximum depth of 85 feet. The lake covers 564 acres.
What fish are in Black Oak Lake?
- Fish species found in Black Oak Lake include Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Trout, Walleye. Black Oak Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Black Oak Lake?
- Wisconsin DNR rates Panfish as abundant on Black Oak Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Black Oak Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Black Oak Lake?
- Black Oak Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Black Oak Lake. Public access is listed as yes.
Explore Black Oak Lake across LakeQuality
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Where this data comes from
48 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_WQX48 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)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory