Half Moon Lake
Bayfield County, Wisconsin106 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Half Moon Lake. Here is what has been measured.
- Mesotrophic
- 10 ft max depth
- Public access
Half Moon Lake in Bayfield County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 17.2 µg/L. Maximum depth: 10 ft. Surface area: 106 acres.
Wisconsin DNR lists Panfish as common on Half Moon Lake. DNR survey details →
Half Moon Lake is a 106-acre mesotrophic lake in Bayfield County, Wisconsin with a maximum depth of 10 feet. Overall water quality is improving 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 23 other monitored lakes in Bayfield County, Half Moon Lake ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-26. Methodology: how these readings are compared.
What Half Moon 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 Half Moon 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 Half Moon Lake
These are the measurements Wisconsin DNR publishes for Half Moon 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 8 ft. Phosphorus 17.2 µg/L. TSI 46.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 17.2µg/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. | 46 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Half Moon Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Panfish as common on Half Moon Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Half Moon Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. 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 2014. 2 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
10 ft
Surface area
106 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
3 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.4 mi
HydroLAKES / HydroSHEDS
Elevation
1,096 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Half Moon LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Half Moon Lake
Compare lakeside cabins, hotels, and vacation rentals near Half Moon Lake in Bayfield 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 Half Moon Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Half Moon Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving4 years
Phosphorus
Improving-0.38 µg/L/yr6 years
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Half Moon Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Iron River Sanitary District 1Iron River · 0.5 mi away · NPDES WI0022446Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Bayfield County
Frequently asked questions about Half Moon Lake
Where is Half Moon Lake?
- Half Moon Lake is a lake in Bayfield County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Half Moon Lake?
- Half Moon Lake in Bayfield County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8 ft visibility. Phosphorus: 17.2 µg/L. Maximum depth: 10 ft. Surface area: 106 acres.
Is Half Moon Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Half Moon Lake?
- Half Moon Lake has a maximum depth of 10 feet. The lake covers 106 acres.
What fish are in Half Moon Lake?
- Fish species found in Half Moon Lake include Panfish, Largemouth Bass, Northern Pike. Half Moon Lake is located in Bayfield County, Wisconsin.
What did the DNR fisheries survey find at Half Moon Lake?
- Wisconsin DNR lists Panfish as common on Half Moon Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Half Moon Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Half Moon Lake?
- Half Moon Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Half Moon Lake. Public access is listed as yes.
Can I fish at Half Moon Lake?
- Half Moon 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 Half Moon Lake across LakeQuality
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Where this data comes from
31 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_WQX31 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
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