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.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 68.9 ft | A |
| Phosphorus | 7.3 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 24 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 36 ft |
| Surface Area | 155 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).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.937 m/yr | 7 |
| Phosphorus | ↑ Improving | -0.61 µg/L/yr | 5 |
Location
County Ranking
Ranked #102 of 202 lakes in Vilas County
Nearby Lakes in Vilas County
More Wisconsin Lake Rankings
Other Grade A Lakes in Wisconsin
Waukesha County · Clarity: 14.6 ft
Waukesha County · Clarity: 13.8 ft
Walworth County · Clarity: 19 ft
Washington County · Clarity: 12 ft
Kenosha County · Clarity: 10.1 ft
Washington County · Clarity: 12.5 ft
Oligotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1993. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
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