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Clear Lake

Lincoln County, WisconsinOligotrophic

Clear Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.

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. A maximum depth of 45 ft puts Clear Lake in the middle of Wisconsin's depth distribution. Clear Lake covers 259 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Lincoln County's 18 graded waters, Clear Lake sits at rank 1, near the top of the local distribution.

Clear Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. Walleye are documented at Clear Lake, one of 4 fish species on record for the 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 2024-10-14. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 18 ft down. Phosphorus level: 10.6 µg/L. Trophic State Index: 37.

MetricValueGrade
Water Clarity (Secchi Depth)18 ftA
Phosphorus10.6 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)37Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth45 ft
Surface Area259 acres

Fish Species

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

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

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

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

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Eurasian Water-Milfoil

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+1.36 m/yr6
Phosphorus Improving-2.7 µg/L/yr6
See year-by-year chart →

Location

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County Ranking

Ranked #1 of 18 lakes in Lincoln County

Nearby Lakes in Lincoln County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2024).

DNR Assessment
Excellent · Deep Seepage lake
Trophic State Index 36 (oligotrophic) · 5-year average

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Common)Northern Pike(Present)Walleye(Present)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2024-10-14

Monitoring stations: 1