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Horsehead Lake

Vilas County, WisconsinMesotrophic

Horsehead Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Vilas County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Mesotrophic conditions dominate at Horsehead Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Among the 191 graded lakes in Vilas County, Horsehead Lake sits at rank 63, above the county median.

Horsehead Lake has no invasive species recorded in Wisconsin state databases as of 2024, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Horsehead Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-08-27. Grade methodology: LakeGrade methodology.

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Good clarity, visible to about 10 ft. Phosphorus level: 14.6 µg/L. Trophic State Index: 43.

MetricValueGrade
Water Clarity (Secchi Depth)10 ftB
Phosphorus14.6 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)43Mesotrophic

Moderate nutrients, good water quality

Water Quality Trend: Improving

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.086 m/yr6
Phosphorus Improving-0.68 µg/L/yr5
See year-by-year chart →

Recreation & Access

2
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #63 of 191 lakes in Vilas County

Nearby Lakes in Vilas County

EPA Impairment Status

Horsehead Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)

Source: EPA ATTAINS assessment unit WI10007691 · Official waterbody report · Matched by proximity (2.68 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Public boat-access points from the USGS National Boat Ramps inventory

Most recent sample: 2024-08-27

Monitoring stations: 2

Where to stay near Horsehead Lake

Compare lakeside cabins, hotels, and vacation rentals near Horsehead Lake in Vilas County, Wisconsin — live availability and prices for your trip.

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