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LakeQuality
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Eagle Lake

Bayfield County, WisconsinOligotrophic

On the LakeGrade rubric, Eagle Lake pulls an A: clarity at 59.1 ft and 14 µg/L of phosphorus put it in the top bracket for Wisconsin. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. At 52 ft of maximum depth, Eagle Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. At 163 acres, Eagle Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Eagle Lake ranks 22 of 55 in Bayfield County — solidly in the upper half of the local distribution.

Eagle Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. Walleye are documented at Eagle Lake, one of 6 fish species on record for the lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-09-07. Grade methodology: LakeGrade methodology.

Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 59.1 ft down. Phosphorus level: 14.3 µg/L. Trophic State Index: 30.

MetricValueGrade
Water Clarity (Secchi Depth)59.1 ftA
Phosphorus14.3 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)30Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth52 ft
Surface Area163 acres

Fish Species

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Eagle Lake (14-day solunar calendar)

→ Is it safe to eat fish from Eagle Lake? (mercury & PFAS guide)

Eagle Lake fishing regulations (limits, seasons, special rules)

Invasive Species

Chinese Mystery SnailEurasian Water-Milfoil

Water Quality Trend: Improving

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+1.545 m/yr7
Phosphorus Improving-0.79 µg/L/yr6

Location

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County Ranking

Ranked #22 of 55 lakes in Bayfield County

Nearby Lakes in Bayfield County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1991. 5 stations on file (most recent sample 2025).

DNR Assessment
Excellent · Deep Lowland lake
Trophic State Index 40 (oligotrophic) · 5-year average

Fish Species (DNR-rated)

Largemouth Bass(Abundant)Panfish(Common)Smallmouth Bass(Common)Walleye(Common)Musky(Present)Northern Pike(Present)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Fish and recreation data from Wisconsin DNR Lakes

Most recent sample: 2025-09-07

Monitoring stations: 1