Siskiwit Lake
Siskiwit Lake in Keweenaw County, Michigan has a water quality grade of B (Good). Water clarity: 20.5 ft visibility. Phosphorus: 4.4 µg/L. Surface area: 4007.7 acres.
- Clarity
- 20.5 ft
- Typical in August
- 55°F
- Max depth
- ~90 ft est.
- Area
- 4,008 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
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Siskiwit Lake is a 4,008-acre cold, clear oligotrophic lake in Keweenaw County, Michigan with an estimated average depth of about 90 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 2 documented fish species including Lake herring and Lake whitefish. Compared to the 10 other monitored lakes in Keweenaw County, Siskiwit Lake ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2024-07-26. 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)
Crystal clear, you can see 20.5 ft down. Phosphorus level: 4.4 µg/L. Trophic State Index: 30.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 20.5 ft | Not graded |
| Phosphorus | 4.4 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 30 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Siskiwit Lake
Compare lakeside cabins, hotels, and vacation rentals near Siskiwit 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.
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Water Temperature
Siskiwit Lake typically sits around 55°F at the surface in August. Summer average is about 52°F. Usually warmest in Aug (about 55°F) and coldest in Jun (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,747 field readings (2010–2024) via the EPA Water Quality Portal. See the full Siskiwit Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~90 ft est. |
| Average Depth | ~40 ft est. |
| Surface Area | 4,008 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 Siskiwit 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 Siskiwit Lake
- Malone Bay2.3 km
- Hatchet Lake4.5 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 Siskiwit Lake
Water Quality Trend: ↓ Declining
Based on 9 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.075 m/yr | 9 |
| Phosphorus | ↓ Declining | +2.29 µg/L/yr | 7 |
EPA Impairment Status
Siskiwit Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI040203000001-02 · Official waterbody report
County Ranking
Ranked #10 of 11 lakes in Keweenaw County
Nearby Lakes in Keweenaw County
Frequently asked questions about Siskiwit Lake
Where is Siskiwit Lake?
- Siskiwit 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 Siskiwit Lake?
- Siskiwit Lake in Keweenaw County, Michigan has a water quality grade of B (Good). Water clarity: 20.5 ft visibility. Phosphorus: 4.4 µg/L. Surface area: 4007.7 acres.
Is Siskiwit Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Siskiwit Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Siskiwit Lake?
- Siskiwit Lake typically sits around 55°F at the surface in August, from 1,747 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Siskiwit Lake?
- No published bathymetric survey covers Siskiwit Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 90 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 4007.7 acres.
What fish are in Siskiwit Lake?
- Fish species found in Siskiwit Lake include Lake herring, Lake whitefish. Siskiwit Lake is located in Keweenaw County, Michigan.
Are there campgrounds on Siskiwit Lake?
- Siskiwit Lake has 2 public campgrounds from USGS The National Map within 5 km, including Malone Bay, Hatchet Lake. 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 Siskiwit Lake across LakeQuality
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Other Grade B Lakes in Michigan
Iron County · 5.5 ft
Iron County · 23 ft
Gogebic County · 6.5 ft
Gogebic County · 5 ft
Gogebic County · 3 ft
Gogebic County · 7.5 ft
Oligotrophic Lakes in Michigan
Compare Siskiwit Lake With Nearby Lakes
Where this data comes from
44 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_WQX44 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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Public campgrounds from USGS The National Map Structures, within about 3 miles