Spring Lake
Vilas County, WisconsinOligotrophic
Spring Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.
A TSI value of 37 puts Spring Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Spring Lake reaches 16 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 236 acres, Spring Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Among the 202 graded lakes in Vilas County, Spring Lake ranks 8 — in the top quartile locally.
Spring Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The fishery is bass-led, with 4 documented species across the lake's records. Public access is available — the lake is on the Wisconsin DNR public-access list. 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 2025-10-08. 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 27.9 ft down. Phosphorus level: 16.3 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 27.9 ft | A |
| Phosphorus | 16.3 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 | 16 ft |
| Surface Area | 236 acres |
| Public Access | Yes |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Spring Lake (14-day solunar calendar)
→ Is it safe to eat fish from Spring Lake? (mercury & PFAS guide)
→ Spring Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.431 m/yr | 7 |
| Phosphorus | → Stable | -0.41 µg/L/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #8 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 2007. 2 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Spring Lake covering fish populations, stocking, water quality, and management. 13 reports on file.
- 2025Catfish Lake spring summary report, 2025Fisheries Survey · WI DNR · 2025 (PDF)
- 2025Cranberry Lake spring summary report, 2025Fisheries Survey · WI DNR · 2025 (PDF)
- 2025Eagle Lake spring summary report, 2025Fisheries Survey · WI DNR · 2025 (PDF)
- 2025Johnson Lake spring bass panfish survey, 2025Panfish Survey · WI DNR · 2025 (PDF)
- 2025Little Saint Germain spring walleye/musky netting survey, 2025Netting Survey · WI DNR · 2025 (PDF)
- 2025Razorback Lake spring summary report, 2025Fisheries Survey · WI DNR · 2025 (PDF)
- 2025Trout Lake spring summary report, 2025Trout Survey · WI DNR · 2025 (PDF)
- 2025Upper and Lower Buckatabon spring musky netting survey, 2025Netting Survey · WI DNR · 2025 (PDF)
- 2025Yellow Birch Lake spring summary report, 2025Fisheries Survey · WI DNR · 2025 (PDF)
- 2024Crab Lake spring survey, 2024Fisheries Survey · WI DNR · 2024 (PDF)
- 2024Plum Lake spring survey, 2024Fisheries Survey · WI DNR · 2024 (PDF)
- 2024Presque Isle Chain spring survey, 2024Fisheries Survey · WI DNR · 2024 (PDF)
- 2024Snipe Lake spring survey, 2024Fisheries Survey · WI DNR · 2024 (PDF)
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: 2025-10-08
Monitoring stations: 1