Lost Lake
Vilas County, Wisconsin539 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Lost Lake. Here is what has been measured.
- Eutrophic
- 2 aquatic invasives
- 20 ft max depth
- Public access
Lost Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 4.5 ft visibility. Phosphorus: 34.5 µg/L. Maximum depth: 20 ft. Surface area: 539 acres.
Wisconsin DNR rates Panfish as abundant on Lost Lake. DNR survey details →
Lost Lake is a 539-acre productive, nutrient-rich eutrophic lake in Vilas County, Wisconsin with a maximum depth of 20 feet. Water clarity is declining over recent sampling years. The lake supports 5 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 102 other monitored lakes in Vilas County, Lost Lake ranks #98 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-21. Methodology: how these readings are compared.
What Lost Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing5 species recorded
Swimming conditions
Readings onlyModerate algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lost Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lost Lake
These are the measurements Wisconsin DNR publishes for Lost Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4.5 ft. Phosphorus 34.5 µg/L. TSI 55.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 34.5µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 55 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lost Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lost Lake typically sits around 59°F at the surface in October. Summer average is about 71°F. Usually warmest in Jul (about 73°F) and coldest in Apr (about 48°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (48°F) to its warmest (73°F).
Typical surface water temperature by month, from 136 field readings (2024–2026) via the EPA Water Quality Portal. See the full Lost Lake water temperature breakdown →
Wisconsin DNR rates Panfish as abundant on Lost Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lost Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1993. 5 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
20 ft
Surface area
539 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
18 sq mi
HydroLAKES / HydroSHEDS
Shoreline
4.8 mi
HydroLAKES / HydroSHEDS
Elevation
1,594 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lost LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Lost Lake
Compare lakeside cabins, hotels, and vacation rentals near Lost Lake in Vilas County, Wisconsin — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Lost Lake
Prices for Oct 16–18, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Follow Lost Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Lost Lake
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: Stable
Based on 7 years of monitoring (2020–2026).
Water clarity
Worsening7 years
Phosphorus
Improving-8.51 µg/L/yr5 years
Nearby Lakes in Vilas County
Frequently asked questions about Lost Lake
Where is Lost Lake?
- Lost Lake is a lake in Vilas County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Lost Lake?
- Lost Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 4.5 ft visibility. Phosphorus: 34.5 µg/L. Maximum depth: 20 ft. Surface area: 539 acres.
Is Lost Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Lost Lake?
- Lost Lake typically sits around 59°F at the surface in October, from 136 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Lost Lake?
- Lost Lake has a maximum depth of 20 feet. The lake covers 539 acres.
What fish are in Lost Lake?
- Fish species found in Lost Lake include Musky, Panfish, Largemouth Bass, Northern Pike, Walleye. Lost Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Lost Lake?
- Wisconsin DNR rates Panfish as abundant on Lost Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lost Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Lost Lake?
- Lost Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lost Lake. Public access is listed as yes.
Can I fish at Lost Lake?
- Lost Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Lost Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Vilas County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Northwoods Wisconsin area
Where to stay at Wisconsin's top lakes, each with its readings
Lakes in the Wisconsin River Watershed, ranked by water quality
Wisconsin's cleanest lakes, ranked on agency measurements
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Other Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Compare Lost Lake With Nearby Lakes
Where this data comes from
159 measurements from 2 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX159 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory