Forest Lake
Washington County, Minnesota2,271 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Forest Lake. Here is what has been measured.
- Eutrophic
- Impaired · PCBs
- 3 aquatic invasives
- 37 ft max depth
- Public access
- Limited data
Forest Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.1 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 16.5 µg/L. Maximum depth: 37 ft. Surface area: 2270.93 acres.
Minnesota DNR's Standard Survey on July 7, 2025 caught 7.90 walleye per gill net at Forest Lake. DNR survey details →
Free interactive depth-contour map of Forest Lake, reaching a maximum surveyed depth of 35 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Forest Lake is a 2,271-acre productive, nutrient-rich eutrophic lake in Washington County, Minnesota with a maximum depth of 37 feet. The lake supports 18 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 3 public boat landings. Compared to the 74 other monitored lakes in Washington County, Forest Lake ranks #54 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-17. Methodology: how these readings are compared.
Forest Lake covers about 2,300 acres in Washington County. It has 3 public boat landings, so a lakefront rental is not the only way to get a boat on the water. The median ice-out date is April 9, which is when the open-water season begins. For a place on the water, look through cabin and lake-house rentals near Forest Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Forest Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch3 documented ramps
- Fishing18 species recorded
- Ice seasonIce-out around Apr 9
- Deep water37 ft surveyed max depth
- Big water2,271 acres
Swimming conditions
Readings onlyLimited data
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. Forest Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pCBs. Check local advisories before you swim.
Whether Forest Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR 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 Minnesota PCA 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.
Murky, only visible to about 5.1 ft. Phosphorus 28 µg/L. Chlorophyll-a 16.5 µg/L. TSI 55.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 28µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 16.5µg/L | Poor GoodFairPoor |
| 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 Forest Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Forest Lake typically sits around 55°F at the surface in October. Summer average is about 69°F. Usually warmest in Jul (about 70°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (55°F) to its warmest (70°F).
Typical surface water temperature by month, from 171 field readings (2011–2024) via the EPA Water Quality Portal. See the full Forest Lake water temperature breakdown →
Minnesota DNR's Standard Survey on July 7, 2025 caught 7.90 walleye per gill net at Forest Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Forest Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
20 surveys on file from MN DNR Fisheries. Most recent: 2025-07-07 (Standard Survey).
20 surveys on file · most recent 2025-07-07 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 32.29 | 2–7 in 2025-07-07 | 0.11 lb |
| Black Crappie | 8.40 | 6–10 in 2025-07-07 | 0.17 lb |
| Spottail Shiner | 7.16 | ||
| Yellow Perch | 7.00 | 4–8 in 2025-07-07 | 0.1 lb |
| Pumpkinseed | 6.76 | 3–7 in 2025-07-07 | 0.16 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Bluegill
Black Crappie
Yellow Perch
Pumpkinseed
From the 2025-07-07 survey
Forest Lake is a 2,251 acre lake comprised of three distinct basins and assigned to lake class 24. There are three public boat accesses available on the lake resulting in high recreational use. Zebra Mussels were discovered in 2015. The primary management species in the lake are Walleye and Muskellunge both of which…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Forest Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ForestFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — ForestFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — ForestPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
37 ft
Surface area
2,271 acres
Shoreline
15.7 mi
Littoral zone
67%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
47 sq mi
HydroLAKES / HydroSHEDS
Elevation
889 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Forest Lake #3Public
- Forest Lake #2 - Willow PointPublic
- Forest Lake #1 - Lakeside ParkPublic
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 Washington County, Minnesota — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Forest Lake are listed below.
Top-rated places to stay near Forest Lake
Prices for Oct 9–11, 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 Minnesota’s top lakes →
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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.
Ice season
Typical ice-out
Apr 9
Earliest Mar 3, 2024 · Latest May 2, 2013
Typical ice-in
Nov 30
Earliest Nov 4, 1991 · Latest Dec 20, 2001
Most recent ice-out
Mar 31
2026
142 observations · Minnesota PCA ice records
EPA Impairment Status
Forest Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN82-0159-00 · Official waterbody report
Nearby Lakes in Washington County
Frequently asked questions about Forest Lake
Where is Forest Lake?
- Forest Lake is a lake in Washington County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Forest Lake?
- Forest Lake in Washington County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.1 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 16.5 µg/L. Maximum depth: 37 ft. Surface area: 2270.93 acres.
Is Forest Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Forest Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pCBs. Check local advisories before you swim.
What is the water temperature of Forest Lake?
- Forest Lake typically sits around 55°F at the surface in October, from 171 EPA Water Quality Portal field readings (2011–2024). That is a typical value for the month, not a live reading.
How deep is Forest Lake?
- Forest Lake has a maximum depth of 37 feet. The lake covers 2270.93 acres.
What fish are in Forest Lake?
- Fish species found in Forest Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, muskellunge, northern pike, pumpkinseed, rock bass, walleye, white crappie, white sucker, yellow bullhead, yellow perch. Forest Lake is located in Washington County, Minnesota.
What did the DNR fisheries survey find at Forest Lake?
- Minnesota DNR's Standard Survey on July 7, 2025 caught 7.90 walleye per gill net at Forest Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Forest Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
When does Forest Lake thaw?
- Forest Lake typically has ice-out around Apr 9. Ice typically forms around Nov 30. The open water season is approximately 235 days.
Are there boat ramps on Forest Lake?
- Forest Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Forest Lake #3, Forest Lake #2 - Willow Point, Forest Lake #1 - Lakeside Park. Public access is listed as yes.
Can I fish at Forest Lake?
- Forest Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota'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 Minnesota
Fish species and best lakes in Washington County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the St. Croix Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Forest Lake
Other Lakes in Minnesota
Eutrophic Lakes in Minnesota
Compare Forest Lake With Nearby Lakes
Where this data comes from
173 measurements from 4 monitoring stations, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA173 samples · 2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
Monitoring station identifiers (4)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate