Feldtmann Lake
Feldtmann Lake in Keweenaw County, Michigan has a water quality grade of B (Good). Water clarity: 7.5 ft visibility. Phosphorus: 11.5 µg/L. Surface area: 462 acres.
- Clarity
- 7.5 ft
- Typical in August
- 70°F
- Max depth
- ~42 ft est.
- Area
- 462 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
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Feldtmann Lake is a 462-acre mesotrophic lake in Keweenaw County, Michigan with an estimated average depth of about 42 feet. Water quality is graded B based on 1 sampling years through 2024. Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including Northern pike, White sucker, and Yellow perch. Compared to the 10 other monitored lakes in Keweenaw County, Feldtmann Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2024-08-19. Grade methodology: LakeQuality 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)
Moderate clarity, visible to about 7.5 ft. Phosphorus level: 11.5 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.5 ft | Not graded |
| Phosphorus | 11.5 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Feldtmann Lake
Compare lakeside cabins, hotels, and vacation rentals near Feldtmann Lake in Keweenaw County, Michigan — 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 Feldtmann Lake
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Water Temperature
Feldtmann Lake typically sits around 70°F at the surface in August. Summer average is about 69°F. Usually warmest in Jul (about 71°F) and coldest in May (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 424 field readings (2010–2024) via the EPA Water Quality Portal. See the full Feldtmann Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~42 ft est. |
| Average Depth | ~15 ft est. |
| Surface Area | 462 acres |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Michigan has not published bathymetry for Feldtmann Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
Public campgrounds near Feldtmann Lake
- Feldtmann Lake0.9 km
- Grace Island4.2 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Feldtmann Lake
Water Quality Trend: ↓ Declining
Based on 9 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.049 m/yr | 9 |
| Phosphorus | ↓ Declining | +3.84 µg/L/yr | 9 |
County Ranking
Ranked #7 of 11 lakes in Keweenaw County
Nearby Lakes in Keweenaw County
Frequently asked questions about Feldtmann Lake
Where is Feldtmann Lake?
- Feldtmann Lake is a lake in Keweenaw County, Michigan. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Feldtmann Lake?
- Feldtmann Lake in Keweenaw County, Michigan has a water quality grade of B (Good). Water clarity: 7.5 ft visibility. Phosphorus: 11.5 µg/L. Surface area: 462 acres.
Is Feldtmann Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Feldtmann Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Feldtmann Lake?
- Feldtmann Lake typically sits around 70°F at the surface in August, from 424 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Feldtmann Lake?
- No published bathymetric survey covers Feldtmann Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 42 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 462 acres.
What fish are in Feldtmann Lake?
- Fish species found in Feldtmann Lake include Northern pike, White sucker, Yellow perch. Feldtmann Lake is located in Keweenaw County, Michigan.
Are there campgrounds on Feldtmann Lake?
- Feldtmann Lake has 2 public campgrounds from USGS The National Map within 5 km, including Feldtmann Lake, Grace Island. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Feldtmann Lake across LakeQuality
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Moderate nutrients, good water quality
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Other Grade B Lakes in Michigan
Iron County · 5.5 ft
Gogebic County · 6.5 ft
Gogebic County · 3 ft
Gogebic County · 5 ft
Gogebic County · 7.5 ft
Iron County · 23 ft
Mesotrophic Lakes in Michigan
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Where this data comes from
50 measurements from 1 monitoring station, 2016–2024. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- National Park Service Water Resources Division
11NPSWRD_WQX50 samples · 2016–2024
Analytical methods
- Secchi Disk
- Alkaline Persulfate Digestion for Total N and P in Water
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)
Public campgrounds from USGS The National Map Structures, within about 3 miles