Thunder Lake
Thunder Lake in Marinette County, Wisconsin has a water quality grade of B (Good). Water clarity: 18 ft visibility. Phosphorus: 10.6 µg/L. Maximum depth: 62 ft. Surface area: 133 acres.
- Clarity
- 18 ft
- Max depth
- 62 ft
- Area
- 133 acres
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
Next lake in Marinette County
Thunder Lake is a 133-acre cold, clear oligotrophic lake in Marinette County, Wisconsin with a maximum depth of 62 feet. Water quality is graded B based on 1 sampling years through 2026. Water clarity is improving over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Trout. Public access is available with 1 public boat landing. Compared to the 9 other monitored lakes in Marinette County, Thunder Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-10. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Crystal clear, you can see 18 ft down. Phosphorus level: 10.6 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 18 ft | Not graded |
| Phosphorus | 10.6 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Thunder Lake
Compare lakeside cabins, hotels, and vacation rentals near Thunder Lake in Marinette 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.
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 62 ft |
| Surface Area | 133 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Thunder LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Thunder 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. Monitored by volunteers since 1988. 17 stations on file (most recent sample 2026).
Fish Species (DNR-rated)
Water Quality Trend: → Stable
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.446 m/yr | 7 |
| Phosphorus | ↓ Declining | +2.55 µg/L/yr | 5 |
County Ranking
Ranked #3 of 10 lakes in Marinette County
Nearby Lakes in Marinette County
Frequently asked questions about Thunder Lake
What is the water quality grade for Thunder Lake?
- Thunder Lake in Marinette County, Wisconsin has a water quality grade of B (Good). Water clarity: 18 ft visibility. Phosphorus: 10.6 µg/L. Maximum depth: 62 ft. Surface area: 133 acres.
Is Thunder Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Thunder Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Thunder Lake?
- Thunder Lake has a maximum depth of 62 feet. The lake covers 133 acres.
What fish are in Thunder Lake?
- Fish species found in Thunder Lake include Panfish, Largemouth Bass, Trout. Thunder Lake is located in Marinette County, Wisconsin.
Are there boat ramps on Thunder Lake?
- Thunder Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Thunder Lake. Public access is listed as yes.
Explore Thunder Lake across LakeGrade
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Fish species and best lakes in Marinette County
Species activity outlook by water temperature and season
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Low nutrients, clear water, excellent for swimming
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State Parks Near Thunder Lake
Other Grade B Lakes in Wisconsin
Oligotrophic Lakes in Wisconsin
Where this data comes from
67 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_WQX67 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory