Horn Lake
Oconto County, Wisconsin131 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Horn Lake. Here is what has been measured.
- Mesotrophic
- 11 ft max depth
- Public access
Horn Lake in Oconto County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8.8 ft visibility. Phosphorus: 14.5 µg/L. Maximum depth: 11 ft. Surface area: 131 acres.
Wisconsin DNR lists Panfish as common on Horn Lake. DNR survey details →
Horn Lake is a 131-acre mesotrophic lake in Oconto County, Wisconsin with a maximum depth of 11 feet. Water clarity is declining over recent sampling years. The lake supports 4 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 2 public boat landings. Compared to the 38 other monitored lakes in Oconto County, Horn Lake ranks #24 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-19. Methodology: how these readings are compared.
What Horn Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
- Fishing4 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 Horn 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 Horn Lake
These are the measurements Wisconsin DNR publishes for Horn 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 8.8 ft. Phosphorus 14.5 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 14.5µg/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. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Horn Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Horn Lake typically sits around 48°F at the surface in November. Summer average is about 75°F. Usually warmest in Jun (about 75°F) and coldest in Nov (about 48°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (48°F) to its warmest (75°F).
Typical surface water temperature by month, from 8 field readings (2024–2025) via the EPA Water Quality Portal. See the full Horn Lake water temperature breakdown →
Wisconsin DNR lists Panfish as common on Horn Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Horn Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. 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. 6 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
11 ft
Surface area
131 acres
Public access
Yes
Listed by Wisconsin DNR
Recreation & Access
- Horn LakePublic
- McCaslin BrookPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Horn Lake
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Top-rated places to stay near Horn Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Horn 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.
Water Quality Trend: Stable
Based on 7 years of monitoring (2020–2026).
Water clarity
Worsening7 years
Phosphorus
Improving-1.14 µg/L/yr5 years
Nearby Lakes in Oconto County
Frequently asked questions about Horn Lake
Where is Horn Lake?
- Horn Lake is a lake in Oconto County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Horn Lake?
- Horn Lake in Oconto County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8.8 ft visibility. Phosphorus: 14.5 µg/L. Maximum depth: 11 ft. Surface area: 131 acres.
Is Horn Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Horn Lake?
- Horn Lake typically sits around 48°F at the surface in November, from 8 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Horn Lake?
- Horn Lake has a maximum depth of 11 feet. The lake covers 131 acres.
What fish are in Horn Lake?
- Fish species found in Horn Lake include Panfish, Largemouth Bass, Northern Pike, Walleye. Horn Lake is located in Oconto County, Wisconsin.
What did the DNR fisheries survey find at Horn Lake?
- Wisconsin DNR lists Panfish as common on Horn Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Horn Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Horn Lake?
- Horn Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Horn Lake, McCaslin Brook. Public access is listed as yes.
Can I fish at Horn Lake?
- Horn Lake has 2 documented boat landings 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 Horn Lake across LakeQuality
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Where this data comes from
18 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX18 samples · 2020–2026
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
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory