Halfmoon Lake
Halfmoon Lake in Lincoln County, Wisconsin has a water quality grade of B (Good). Water clarity: 7.1 ft visibility. Phosphorus: 19.4 µg/L. Maximum depth: 14 ft. Surface area: 102 acres.
- Clarity
- 7.1 ft
- Max depth
- 14 ft
- Area
- 102 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Lincoln County
Halfmoon Lake is a 102-acre mesotrophic lake in Lincoln County, Wisconsin with a maximum depth of 14 feet. Water quality is graded B based on 1 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 2 public boat landings. Compared to the 12 other monitored lakes in Lincoln County, Halfmoon Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-27. Grade methodology: LakeGrade 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)
Moderate clarity, visible to about 7.1 ft. Phosphorus level: 19.4 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.1 ft | Not graded |
| Phosphorus | 19.4 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Halfmoon Lake
Compare lakeside cabins, hotels, and vacation rentals near Halfmoon Lake in Lincoln 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 | 14 ft |
| Surface Area | 102 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Jersey City Flowage - 1Public
- Halfmoon LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Halfmoon Lake
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1999. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.589 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.69 µg/L/yr | 6 |
County Ranking
Ranked #6 of 13 lakes in Lincoln County
Nearby Lakes in Lincoln County
Frequently asked questions about Halfmoon Lake
What is the water quality grade for Halfmoon Lake?
- Halfmoon Lake in Lincoln County, Wisconsin has a water quality grade of B (Good). Water clarity: 7.1 ft visibility. Phosphorus: 19.4 µg/L. Maximum depth: 14 ft. Surface area: 102 acres.
Is Halfmoon Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Halfmoon Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Halfmoon Lake?
- Halfmoon Lake has a maximum depth of 14 feet. The lake covers 102 acres.
What fish are in Halfmoon Lake?
- Fish species found in Halfmoon Lake include Panfish, Largemouth Bass, Northern Pike. Halfmoon Lake is located in Lincoln County, Wisconsin.
Are there boat ramps on Halfmoon Lake?
- Halfmoon Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Jersey City Flowage - 1, Halfmoon Lake. Public access is listed as yes.
Explore Halfmoon Lake across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
32 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX32 samples · 2020–2025
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)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory