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Little Trout Lake Deep

Vilas County, WisconsinLimited DataOligotrophic

Little Trout Lake Deep sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Trophically, Little Trout Lake Deep reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. Little Trout Lake Deep is unusually deep for Wisconsin at 98 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. At 1,007 acres, Little Trout Lake Deep is one of the larger lakes in Vilas County, with partial shoreline records supporting multiple distinct use patterns. Little Trout Lake Deep sits at rank 114 of 202 in Vilas County, in the lower half of the local distribution.

No invasive species are currently listed at Little Trout Lake Deep — 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 2020-07-29. 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 49.2 ft down. Trophic State Index: 21.

MetricValueGrade
Water Clarity (Secchi Depth)49.2 ftA
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)21Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth98 ft
Surface Area1.0K acres

Fish Species

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

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

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

Little Trout Lake Deep fishing regulations (limits, seasons, special rules)

Water Quality Trend: Improving

Based on 3 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Phosphorus Improving-0.33 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #114 of 202 lakes in Vilas County

Nearby Lakes in Vilas County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 5 stations on file (most recent sample 2003).

Fish Species (DNR-rated)

Musky(Common)Smallmouth Bass(Common)Walleye(Common)Panfish(Present)Largemouth Bass(Present)Trout(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: 2020-07-29

Monitoring stations: 1