Two Sisters Lake
Two Sisters Lake in Oneida County, Wisconsin has a water quality grade of B (Good). Water clarity: 19.6 ft visibility. Phosphorus: 10.8 µg/L.
- Clarity
- 19.6 ft
- Typical in August
- 70°F
- Max depth
- ~51 ft est.
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- Yes
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Two Sisters Lake is a cold, clear oligotrophic lake in Oneida County, Wisconsin with an estimated average depth of about 51 feet. Water quality is graded B based on 1 sampling years through 2025. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 66 other monitored lakes in Oneida County, Two Sisters Lake ranks #33 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-29. 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 19.6 ft down. Phosphorus level: 10.8 µg/L. Trophic State Index: 36.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 19.6 ft | Not graded |
| Phosphorus | 10.8 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Two Sisters Lake
Compare lakeside cabins, hotels, and vacation rentals near Two Sisters Lake in Oneida 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
Two Sisters Lake typically sits around 70°F at the surface in August. Summer average is about 71°F. Usually warmest in Jul (about 74°F) and coldest in May (about 53°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 24 field readings (2024–2025) via the EPA Water Quality Portal. See the full Two Sisters Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~51 ft est. |
| Average Depth | ~18 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wisconsin has not published bathymetry for Two Sisters 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
- Two Sisters LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Two Sisters Lake
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.223 m/yr | 6 |
| Phosphorus | ↓ Declining | +1.81 µg/L/yr | 5 |
County Ranking
Ranked #33 of 67 lakes in Oneida County
Nearby Lakes in Oneida County
Frequently asked questions about Two Sisters Lake
Where is Two Sisters Lake?
- Two Sisters Lake is a lake in Oneida County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Two Sisters Lake?
- Two Sisters Lake in Oneida County, Wisconsin has a water quality grade of B (Good). Water clarity: 19.6 ft visibility. Phosphorus: 10.8 µg/L.
Is Two Sisters Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Two Sisters Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Two Sisters Lake?
- Two Sisters Lake typically sits around 70°F at the surface in August, from 24 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Two Sisters Lake?
- No published bathymetric survey covers Two Sisters Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 51 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 Two Sisters Lake?
- Two Sisters Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Two Sisters Lake. Public access is listed as yes.
Explore Two Sisters Lake across LakeQuality
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Where this data comes from
58 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX58 samples · 2020–2025
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