Feldtmann Lake
Keweenaw County, Michigan462 acresView mapDirections
EGLE publishes the water-quality measurements for Feldtmann Lake. Here is what has been measured.
- Mesotrophic
- 42 ft max depth
Feldtmann Lake in Keweenaw County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 7.5 ft visibility. Phosphorus: 11.5 µg/L. Surface area: 462 acres.
Feldtmann Lake is a 462-acre mesotrophic lake in Keweenaw County, Michigan with an estimated average depth of about 42 feet. 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. Methodology: how these readings are compared.
What Feldtmann Lake is good for
From access and monitoring records, not editorial picks.
- Fishing3 species recorded
- Camping2 public campgrounds nearby
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Feldtmann Lake is safe to swim in today is a call for the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Feldtmann Lake
These are the measurements EGLE publishes for Feldtmann Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7.5 ft. Phosphorus 11.5 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 11.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Feldtmann Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Feldtmann Lake typically sits around 70°F at the surface in September. 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.
Column height runs from this lake’s coldest month (49°F) to its warmest (71°F).
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
Max depth
~42 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
Watershed (drainage) area
5 sq mi
HydroLAKES / HydroSHEDS
Shoreline
3.9 mi
HydroLAKES / HydroSHEDS
Elevation
650 ft
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
Stays via Stay22
Stays 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
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Fish Species
Click a species to see every lake where it is documented.
Fishing Feldtmann Lake
Water Quality Trend: Worsening
Based on 9 years of monitoring (2016–2024).
Water clarity
Worsening9 years
Phosphorus
Worsening+3.84 µg/L/yr9 years
Nearby Lakes in Keweenaw County
Frequently asked questions about Feldtmann Lake
Where is Feldtmann Lake?
- Feldtmann Lake is a lake in Keweenaw County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Feldtmann Lake?
- Feldtmann Lake in Keweenaw County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 7.5 ft visibility. Phosphorus: 11.5 µg/L. Surface area: 462 acres.
Is Feldtmann Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Feldtmann Lake?
- Feldtmann Lake typically sits around 70°F at the surface in September, 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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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)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Public campgrounds from USGS The National Map Structures, within about 3 miles