Little John Jr Lake
Little John Jr Lake in Vilas County, Wisconsin has a water quality grade of C (Fair). Water clarity: 10 ft visibility. Phosphorus: 26.2 µg/L.
- Clarity
- 10 ft
- Max depth
- ~24 ft est.
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- Yes
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Little John Jr Lake is a mesotrophic lake in Vilas County, Wisconsin with an estimated average depth of about 24 feet. Water quality is graded C based on 1 sampling years through 2022. 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 102 other monitored lakes in Vilas County, Little John Jr Lake ranks #102 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-08-02. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited data
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Good clarity, visible to about 10 ft. Phosphorus level: 26.2 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 26.2 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Little John Jr Lake
Compare lakeside cabins, hotels, and vacation rentals near Little John Jr 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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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~24 ft est. |
| Average Depth | ~10 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 Little John Jr 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
- Big Muskellunge Lake 2Public
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Little John Jr 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: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +2.2 µg/L/yr | 2 |
County Ranking
Ranked #102 of 103 lakes in Vilas County
Nearby Lakes in Vilas County
Frequently asked questions about Little John Jr Lake
Where is Little John Jr Lake?
- Little John Jr Lake is a lake in Vilas County, Wisconsin. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Little John Jr Lake?
- Little John Jr Lake in Vilas County, Wisconsin has a water quality grade of C (Fair). Water clarity: 10 ft visibility. Phosphorus: 26.2 µg/L.
Is Little John Jr Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Little John Jr Lake has a water quality grade of C (Fair). Always check local health department advisories before swimming.
How deep is Little John Jr Lake?
- No published bathymetric survey covers Little John Jr Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 24 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 Little John Jr Lake?
- Little John Jr Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big Muskellunge Lake 2. Public access is listed as yes.
Explore Little John Jr Lake across LakeQuality
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Moderate nutrients, good water quality
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Where this data comes from
5 measurements from 1 monitoring station, 2021–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX5 samples · 2021–2022
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
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