Long Interlaken Lake Deep
Vilas County, WisconsinLimited DataOligotrophic
Long Interlaken Lake Deep 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.
Trophically, Long Interlaken Lake Deep reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. Long Interlaken Lake Deep is unusually deep for Wisconsin at 65 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. Long Interlaken Lake Deep covers 380 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Vilas County's 191 graded waters, Long Interlaken Lake Deep sits at rank 23, near the top of the local distribution.
Long Interlaken Lake Deep has at least one documented invasive species (Banded Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Long Interlaken Lake Deep, one of 6 fish species on record for the 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 2020-10-06. Grade methodology: LakeGrade methodology.
Watch Long Interlaken Lake Deep water quality
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 15 ft down. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 65 ft |
| Surface Area | 380 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Long Interlaken Lake Deep (14-day solunar calendar)
→ Is it safe to eat fish from Long Interlaken Lake Deep? (mercury & PFAS guide)
→ Long Interlaken Lake Deep fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↑ Improving | -0.74 µg/L/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #23 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
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2019).
Fish Species (DNR-rated)
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
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2020-10-06
Monitoring stations: 1
Where to stay near Long Interlaken Lake Deep
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