Forest Lake
Vilas County, Wisconsin468 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Forest Lake. Here is what has been measured.
- Oligotrophic
- 60 ft max depth
- Public access
Forest Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 22.2 ft visibility. Phosphorus: 12.8 µg/L. Maximum depth: 60 ft. Surface area: 468 acres.
Wisconsin DNR lists Panfish as common on Forest Lake. DNR survey details →
Forest Lake is a 468-acre cold, clear oligotrophic lake in Vilas County, Wisconsin with a maximum depth of 60 feet. The lake supports 5 documented fish species including Panfish, Largemouth Bass, and Smallmouth Bass. Public access is available with 1 public boat landing. Compared to the 102 other monitored lakes in Vilas County, Forest Lake ranks #37 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-15. Methodology: how these readings are compared.
What Forest Lake is good for
From access and monitoring records, not editorial picks.
- Clear water22.2 ft of visibility
- Boat launch1 documented ramp
- Fishing5 species recorded
- Deep water60 ft surveyed max depth
Swimming conditions
Readings onlyLow 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 Forest 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 Forest Lake
These are the measurements Wisconsin DNR publishes for Forest Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 22.2 ft down. Phosphorus 12.8 µg/L. TSI 37.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 22.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12.8µg/L | Good 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. | 37 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Forest Lake
Answers come straight from the public measurements and survey records on this page.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Forest Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (84,723 cells/mL) on May 23, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR lists Panfish as common on Forest Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Forest 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 1990. 10 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
60 ft
Surface area
468 acres
Public access
Yes
Listed by Wisconsin DNR
Recreation & Access
- Lac du LunePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Forest Lake
Compare lakeside cabins, hotels, and vacation rentals near Forest 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 Forest Lake
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Follow Forest Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Forest 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
Stable6 years
Phosphorus
Stable-0.06 µg/L/yr7 years
Nearby Lakes in Vilas County
Frequently asked questions about Forest Lake
Where is Forest Lake?
- Forest 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 Forest Lake?
- Forest Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 22.2 ft visibility. Phosphorus: 12.8 µg/L. Maximum depth: 60 ft. Surface area: 468 acres.
Is Forest Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Forest Lake?
- Forest Lake has a maximum depth of 60 feet. The lake covers 468 acres.
What fish are in Forest Lake?
- Fish species found in Forest Lake include Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Forest Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Forest Lake?
- Wisconsin DNR lists Panfish as common on Forest Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Forest 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.
Does Forest Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Forest Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (84,723 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Forest Lake?
- Forest Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lac du Lune. Public access is listed as yes.
Can I fish at Forest Lake?
- Forest 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 Forest 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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Compare Forest Lake With Nearby Lakes
Where this data comes from
46 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX46 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
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
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory