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LakeQuality
A

Carlin Lake

Vilas County, WisconsinOligotrophic

Carlin 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.

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 36 ft puts Carlin Lake in the middle of Wisconsin's depth distribution. At 155 acres, Carlin Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Carlin Lake sits at rank 102 of 202 in Vilas County, in the lower half of the local distribution.

No invasive species are currently listed at Carlin Lake — the lake remains off the Wisconsin infested-waters roster. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. 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 2025-09-14. 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 68.9 ft down. Phosphorus level: 7.3 µg/L. Trophic State Index: 24.

MetricValueGrade
Water Clarity (Secchi Depth)68.9 ftA
Phosphorus7.3 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)24Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth36 ft
Surface Area155 acres

Fish Species

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

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

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

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

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+0.937 m/yr7
Phosphorus Improving-0.61 µg/L/yr5
See year-by-year chart →

Location

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County Ranking

Ranked #102 of 202 lakes in Vilas County

Nearby Lakes in Vilas County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1993. 1 station on file (most recent sample 2025).

DNR Assessment
Excellent · Deep Seepage lake
Trophic State Index 34 (oligotrophic) · 5-year average

Fish Species (DNR-rated)

Panfish(Common)Smallmouth Bass(Common)Largemouth Bass(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: 2025-09-14

Monitoring stations: 1