Siskiwit Lake
Keweenaw County, Michigan4,008 acresView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
↓ down from A at the last regrade
- Oligotrophic
- Impaired · Mercury
- #10 of 11 in the county
- 90 ft max depth
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.
What Siskiwit Lake is good for
From access and monitoring records, not editorial picks.
- Clear water20.5 ft of visibility
- Camping2 public campgrounds nearby
- Big water4,008 acres
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.
The B is nutrients and algae, not a swimming clearance. Siskiwit Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, pCBs. Check local advisories before you swim.
Water Quality Grade: B (Good)
Crystal clear, you can see 20.5 ft down. Phosphorus 4.4 µg/L. TSI 30. The letter is not a swimming clearance.
| 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. The letter is not a swimming clearance.
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?
- The B is nutrients and algae, not a swimming clearance. Siskiwit Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, pCBs. Check local advisories before you swim.
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
Fish species and top-graded lakes across Michigan
Fish species and best lakes in Keweenaw County
Species activity outlook by water temperature and season
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Where to stay at Michigan's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
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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