Neptune Lake
Oneida County, Wisconsin127 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Neptune Lake. Here is what has been measured.
- 7 ft max depth
- Limited data
Neptune Lake in Oneida County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2 ft visibility. Maximum depth: 7 ft. Surface area: 127 acres.
Wisconsin DNR lists Largemouth Bass as common on Neptune Lake. DNR survey details →
Neptune Lake is a 127-acre lake in Oneida County, Wisconsin with a maximum depth of 7 feet. Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Northern Pike.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-09-15. Methodology: how these readings are compared.
What Neptune Lake is good for
From access and monitoring records, not editorial picks.
- Fishing3 species recorded
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Neptune 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 Neptune Lake
These are the measurements Wisconsin DNR publishes for Neptune Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2 ft of visibility. TSI 67.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| 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. | 67 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Neptune Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Largemouth Bass as common on Neptune Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Neptune Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is declining. 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. 1 station on file (most recent sample 2024).
Fish Species (DNR-rated)
Lake Details
Max depth
7 ft
Surface area
127 acres
Lake Size & Watershed
Watershed (drainage) area
5 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.6 mi
HydroLAKES / HydroSHEDS
Elevation
1,601 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
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Stays near Neptune Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Neptune Lake
Water quality readings over time
2 seasons of samples on record (2024–2025). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Nearby Lakes in Oneida County
Frequently asked questions about Neptune Lake
Where is Neptune Lake?
- Neptune Lake is a lake in Oneida County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Neptune Lake?
- Neptune Lake in Oneida County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2 ft visibility. Maximum depth: 7 ft. Surface area: 127 acres.
Is Neptune Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Neptune Lake?
- Neptune Lake has a maximum depth of 7 feet. The lake covers 127 acres.
What fish are in Neptune Lake?
- Fish species found in Neptune Lake include Panfish, Largemouth Bass, Northern Pike. Neptune Lake is located in Oneida County, Wisconsin.
What did the DNR fisheries survey find at Neptune Lake?
- Wisconsin DNR lists Largemouth Bass as common on Neptune Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Neptune Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
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Where this data comes from
3 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX3 samples · 2024
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes