Lost Lake
Lost Lake in Vilas County, Wisconsin has a water quality grade of C (Fair). 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 →
- Clarity
- 4.5 ft
- Typical in August
- 73°F
- Max depth
- 20 ft
- Area
- 539 acres
- Type
- Eutrophic
- Trend
- → Stable
- Public access
- Yes
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Lost Lake is a 539-acre productive, nutrient-rich eutrophic lake in Vilas County, Wisconsin with a maximum depth of 20 feet. Water quality is graded C based on 1 sampling years through 2026. 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. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyModerate
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Murky, only visible to about 4.5 ft. Phosphorus level: 34.5 µg/L. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.5 ft | Not graded |
| Phosphorus | 34.5 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
Lost Lake typically sits around 73°F at the surface in August. 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.
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 a water-quality grade. LakeQuality grades Lost Lake C from EPA Water Quality Portal chemistry, 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
| Characteristic | Value |
|---|---|
| Maximum Depth | 20 ft |
| Surface Area | 539 acres |
| Public Access | Yes |
Lake Size & Watershed
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
Fish Species
Click a species to see every graded 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 data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.1 m/yr | 7 |
| Phosphorus | ↑ Improving | -8.51 µg/L/yr | 5 |
EPA Impairment Status
Lost Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10007601 · Official waterbody report · Matched by proximity (2.56 km)
County Ranking
Ranked #98 of 103 lakes in Vilas County
Nearby Lakes With Higher Grades
Lost Lake holds Grade C. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Vilas County
Frequently asked questions about Lost Lake
Where is Lost Lake?
- Lost Lake is a lake in Vilas County, Wisconsin. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lost Lake?
- Lost Lake in Vilas County, Wisconsin has a water quality grade of C (Fair). 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?
- Generally safe for swimming, moderate water quality. Lost Lake has a water quality grade of C (Fair). Always check local health department advisories before swimming.
What is the water temperature of Lost Lake?
- Lost Lake typically sits around 73°F at the surface in August, 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 a water-quality grade. LakeQuality grades Lost Lake C from EPA Water Quality Portal chemistry, 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.
Explore Lost Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Vilas County
Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
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