Little Rock Lake
Vilas County, WisconsinLimited DataOligotrophic
On the LakeGrade rubric, Little Rock Lake pulls an A: clarity readings still being added and 8 µg/L of phosphorus put it in the top bracket for Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.
Trophically, Little Rock Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Vilas County's 191 graded waters, Little Rock Lake sits at rank 43, near the top of the local distribution.
Little Rock Lake has no invasive species recorded in Wisconsin state databases as of 2026, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Little Rock Lake, which usually reflects a lack of formal fisheries survey work rather than an empty 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 2026-05-14. Grade methodology: LakeGrade methodology.
Watch Little Rock Lake water quality
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
No clarity data. Phosphorus level: 8.3 µg/L. Trophic State Index: 35.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 8.3 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 35 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↑ Improving | -5.2 µg/L/yr | 3 |
Location
County Ranking
Ranked #43 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
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2026-05-14
Monitoring stations: 2
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