Flynn Lake
Flynn Lake in Bayfield County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9 ft visibility. Maximum depth: 9 ft. Surface area: 30 acres.
- Clarity
- 9 ft
- Max depth
- 9 ft
- Area
- 30 acres
- Trend
- ↑ Improving
Next lake in Bayfield County
Why Flynn Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Flynn Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Flynn Lake is a 30-acre lake in Bayfield County, Wisconsin with a maximum depth of 9 feet. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2023-06-01. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Flynn Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Moderate clarity, visible to about 9 ft. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Flynn Lake
Compare lakeside cabins, hotels, and vacation rentals near Flynn Lake in Bayfield 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 Flynn Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 9 ft |
| Surface Area | 30 acres |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Flynn 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.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 2 stations on file (most recent sample 2023).
Fish Species (DNR-rated)
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.825 m/yr | 5 |
| Phosphorus | → Stable | 0 µg/L/yr | 7 |
Reservoir Info (USACE NID)
Flynn Lake is a man-made reservoir impounded by the Murrays (completed 1941), built primarily for recreation on the EAST FORK WHITE; gravity-type dam, 13 ft tall and 34 ft long.
- Surface area
- 650 ac
- Normal storage
- 19,960 ac-ft
- Max storage
- 22,000 ac-ft
- Drainage area
- 13 sq mi
- Hazard class
- Low
- Owner
- Bayfield County
Source: USACE National Inventory of Dams, NID ID WI00103 · Operator website · Matched by proximity (0.25 km)
Graded lakes near Flynn Lake
Flynn Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Bayfield County
Frequently asked questions about Flynn Lake
What is the water quality grade for Flynn Lake?
- Flynn Lake in Bayfield County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9 ft visibility. Maximum depth: 9 ft. Surface area: 30 acres.
Is Flynn Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Flynn Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Flynn Lake?
- Flynn Lake has a maximum depth of 9 feet. The lake covers 30 acres.
What fish are in Flynn Lake?
- Fish species found in Flynn Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Flynn Lake is located in Bayfield County, Wisconsin.
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Where this data comes from
12 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX12 samples · 2020–2023
Monitoring station identifiers (1)
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
Fish and recreation data from Wisconsin DNR Lakes