Crescent Lake
Oneida County, WisconsinOligotrophic
On the LakeGrade rubric, Crescent Lake pulls an A: clarity at 45.9 ft and 13 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.
A TSI value of 32 puts Crescent Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. 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. Among the 140 graded lakes in Oneida County, Crescent Lake ranks 18 — in the top quartile locally.
No invasive species are currently listed at Crescent Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Crescent 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 2025-04-29. 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 45.9 ft down. Phosphorus level: 13.1 µg/L. Trophic State Index: 32.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 45.9 ft | A |
| Phosphorus | 13.1 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 32 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.4 m/yr | 5 |
| Phosphorus | ↑ Improving | -0.41 µg/L/yr | 5 |
Location
County Ranking
Ranked #18 of 140 lakes in Oneida County
Nearby Lakes in Oneida 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
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Crescent Lake covering fish populations, stocking, water quality, and management. 1 report on file.
- 2022Comprehensive Fisheries Survey of Crescent Lake, 2022Comprehensive Survey · WI DNR · 2022 (PDF)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-04-29
Monitoring stations: 2