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Little Spider Lake

Vilas County, WisconsinOligotrophic

Little Spider Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. 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. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. Little Spider Lake covers 223 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 202 graded lakes in Vilas County, Little Spider Lake sits at rank 63, above the county median.

Little Spider Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. Walleye are documented at Little Spider Lake, one of 5 fish species on record for the lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-25. 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 52.5 ft down. Phosphorus level: 11.5 µg/L. Trophic State Index: 30.

MetricValueGrade
Water Clarity (Secchi Depth)52.5 ftA
Phosphorus11.5 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)30Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Surface Area223 acres

Fish Species

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Little Spider Lake (14-day solunar calendar)

→ Is it safe to eat fish from Little Spider Lake? (mercury & PFAS guide)

Little Spider Lake fishing regulations (limits, seasons, special rules)

Invasive Species

Chinese Mystery SnailEurasian Water-MilfoilPurple LoosestrifeRusty Crayfish

Water Quality Trend: Declining

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.329 m/yr6
Phosphorus Stable-0.22 µg/L/yr6
See year-by-year chart →

Location

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County Ranking

Ranked #63 of 202 lakes in Vilas County

Nearby Lakes in Vilas County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1993. 3 stations on file (most recent sample 2025).

DNR Assessment
Good · Shallow Seepage lake
Trophic State Index 45 (mesotrophic) · 5-year average

Fish Species (DNR-rated)

Panfish(Common)Musky(Present)Largemouth Bass(Present)Smallmouth Bass(Present)Walleye(Present)

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: 2025-08-25

Monitoring stations: 1