Trego Lake
Washburn County, Wisconsin383 acresView mapDirections
No nutrient or algae sampling on record from Wisconsin DNR for this lake.
- Impaired · Cause unknown
- Curly-Leaf Pondweed
- 36 ft max depth
- Public access
- Limited data
Trego Lake in Washburn County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Maximum depth: 36 ft. Surface area: 383 acres.
Wisconsin DNR rates Panfish as abundant on Trego Lake. DNR survey details →
Trego Lake is a 383-acre lake in Washburn County, Wisconsin with a maximum depth of 36 feet. The lake supports 7 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-06. Methodology: how these readings are compared.
What Trego Lake is good for
From access and monitoring records, not editorial picks.
- Fishing7 species recorded
- Deep water36 ft surveyed max depth
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Trego Lake is listed impaired under Clean Water Act §303(d) (IR 5R) for cause unknown. Check local advisories before you swim.
Whether Trego 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 Trego Lake
These are the measurements Wisconsin DNR publishes for Trego Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data.
Ask about Trego Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR rates Panfish as abundant on Trego Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Trego Lake’s water-quality measurements separately. 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. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
36 ft
Surface area
383 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
503 sq mi
HydroLAKES / HydroSHEDS
Shoreline
5.5 mi
HydroLAKES / HydroSHEDS
Elevation
1,027 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Trego Lake
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Follow Trego Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Trego 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.
Reservoir Info (USACE NID)
Trego Lake is a man-made reservoir impounded by the Trego (completed 1927), built primarily for hydroelectric on the Namekagon River; gravity-type dam, 39 ft tall and 625 ft long.
- Surface area
- 470 ac
- Normal storage
- 4,700 ac-ft
- Max storage
- 4,700 ac-ft
- Drainage area
- 488 sq mi
- Hazard class
- Significant
- Owner
- Northern States Power Co
All listed purposes: Hydroelectric;Recreation.
Source: USACE National Inventory of Dams, NID ID WI00812 · Operator website
EPA Impairment Status
Trego Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).
Causes of impairment
Designated uses not supporting: Recreation.
Source: EPA ATTAINS assessment unit WI10005676 · Official waterbody report
Nearby Lakes in Washburn County
Frequently asked questions about Trego Lake
Where is Trego Lake?
- Trego Lake is a lake in Washburn County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Trego Lake?
- Trego Lake in Washburn County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Maximum depth: 36 ft. Surface area: 383 acres.
Is Trego Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Trego Lake is listed impaired under Clean Water Act §303(d) (IR 5R) for cause unknown. Check local advisories before you swim.
How deep is Trego Lake?
- Trego Lake has a maximum depth of 36 feet. The lake covers 383 acres.
What fish are in Trego Lake?
- Fish species found in Trego Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye, Sturgeon. Trego Lake is located in Washburn County, Wisconsin.
What did the DNR fisheries survey find at Trego Lake?
- Wisconsin DNR rates Panfish as abundant on Trego Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Trego Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Trego Lake?
- Public access to Trego Lake is listed as yes on the lake record. 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 Trego Lake across LakeQuality
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Where this data comes from
5 measurements from 1 monitoring station, 2024–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX5 samples · 2024–2026
Analytical methods
- Total Phosphorus After Block Digestion
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes