Sunset Lake
Vilas County, WisconsinOligotrophic
Sunset Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Vilas County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.
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 30 ft puts Sunset Lake in the middle of Wisconsin's depth distribution. Sunset Lake covers 207 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Sunset Lake ranks 15 of 191 in Vilas County, putting it in the upper tier of locally monitored lakes.
No invasive species are currently listed at Sunset Lake — the lake remains off the Wisconsin infested-waters roster. The fishery includes walleye alongside the lake's other 6 documented species — a notable draw for Wisconsin anglers. 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 2026-06-02. Grade methodology: LakeGrade methodology.
Watch Sunset Lake water quality
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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 17.5 ft down. Phosphorus level: 11 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 17.5 ft | A |
| Phosphorus | 11 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 30 ft |
| Surface Area | 207 acres |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Sunset Lake (14-day solunar calendar)
→ Is it safe to eat fish from Sunset Lake? (mercury & PFAS guide)
→ Sunset 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 | +1.169 m/yr | 7 |
| Phosphorus | ↑ Improving | -2.03 µg/L/yr | 4 |
Location
County Ranking
Ranked #15 of 191 lakes in Vilas County
Nearby Lakes in Vilas County
More Wisconsin Lake Rankings
Other Grade A Lakes in Wisconsin
Washington County · Clarity: 11.8 ft
Washington County · Clarity: 12.6 ft
Walworth County · Clarity: 11 ft
Waukesha County · Clarity: 11.3 ft
Walworth County · Clarity: 20.2 ft
Kenosha County · Clarity: 10 ft
Oligotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1989. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
EPA Impairment Status
Sunset Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10026161 · Official waterbody report · Matched by proximity (2.3 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
Fish and recreation data from Wisconsin DNR Lakes
Most recent sample: 2026-06-02
Monitoring stations: 2
Where to stay near Sunset Lake
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