Dunn Lake
Washburn County, WisconsinLimited DataOligotrophic
Dunn Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.
A TSI value of 39 puts Dunn Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake bottoms out at 39 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 181 acres, Dunn Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Dunn Lake sits at rank 32 of 47 in Washburn County, in the lower half of the local distribution.
An invasive species record — Chinese Mystery Snail — has been logged at Dunn Lake; Wisconsin DNR maintains the official infested-waters list. Walleye are documented at Dunn Lake, one of 4 fish species on record for the lake. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-08-17. Grade methodology: LakeGrade methodology.
Watch Dunn Lake water quality
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 14.2 ft. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.2 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 39 ft |
| Surface Area | 181 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Dunn Lake (14-day solunar calendar)
→ Is it safe to eat fish from Dunn Lake? (mercury & PFAS guide)
→ Dunn Lake fishing regulations (limits, seasons, special rules)
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: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.5 m/yr | 2 |
Recreation & Access
Location
County Ranking
Ranked #32 of 47 lakes in Washburn County
Cleaner Lakes Within 30 Miles
Dunn Lake holds Grade B. 5 nearby lakes hold higher grades.
Nearby Lakes in Washburn County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Oligotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 2 stations on file (most recent sample 2022).
Fish Species (DNR-rated)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Fish and recreation data from Wisconsin DNR Lakes
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2022-08-17
Monitoring stations: 2
Where to stay near Dunn Lake
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