Halfmoon Lake
Lincoln County, Wisconsin102 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Halfmoon Lake. Here is what has been measured.
- Mesotrophic
- 14 ft max depth
- Public access
Halfmoon Lake in Lincoln County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 7.1 ft visibility. Phosphorus: 19.4 µg/L. Maximum depth: 14 ft. Surface area: 102 acres.
Wisconsin DNR lists Panfish as common on Halfmoon Lake. DNR survey details →
Halfmoon Lake is a 102-acre mesotrophic lake in Lincoln County, Wisconsin with a maximum depth of 14 feet. 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 1 public boat landing. 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. Methodology: how these readings are compared.
What Halfmoon Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing3 species recorded
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Halfmoon 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 Halfmoon Lake
These are the measurements Wisconsin DNR publishes for Halfmoon Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7.1 ft. Phosphorus 19.4 µg/L. TSI 48.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 19.4µg/L | Good GoodFairPoor |
| 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. | 48 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Halfmoon Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Panfish as common on Halfmoon Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Halfmoon Lake’s water-quality measurements separately, and the water-quality trend over 6 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. Monitored by volunteers since 1999. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
14 ft
Surface area
102 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.2 mi
HydroLAKES / HydroSHEDS
Elevation
1,457 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Jersey City Flowage - 1Public
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays 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.
Top-rated places to stay near Halfmoon Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Halfmoon Lake
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Worsening+0.69 µg/L/yr6 years
Nearby Lakes in Lincoln County
Frequently asked questions about Halfmoon Lake
Where is Halfmoon Lake?
- Halfmoon Lake is a lake in Lincoln County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Halfmoon Lake?
- Halfmoon Lake in Lincoln County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. 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?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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.
What did the DNR fisheries survey find at Halfmoon Lake?
- Wisconsin DNR lists Panfish as common on Halfmoon Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Halfmoon Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Halfmoon Lake?
- Halfmoon Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Jersey City Flowage - 1. Public access is listed as yes.
Can I fish at Halfmoon Lake?
- Halfmoon Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Halfmoon Lake across LakeQuality
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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)
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
Named boat-access points from the USGS National Boat Ramps inventory