Siskiwit Lake
Keweenaw County, WisconsinMesotrophic
Siskiwit Lake is a mesotrophic lake in Keweenaw County, MI. Water quality is graded A based on 2 sampling years through 2024. The lake supports 2 documented fish species including Lake herring and Lake whitefish. Compared to the 18 other monitored lakes in Keweenaw County, Siskiwit Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-07-26. Grade methodology: LakeGrade methodology.
Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 19.3 ft down. Phosphorus level: 24.5 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 19.3 ft | A |
| Phosphorus | 24.5 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Siskiwit Lake (14-day solunar calendar)
→ Is it safe to eat fish from Siskiwit Lake? (mercury & PFAS guide)
→ Siskiwit Lake fishing regulations (limits, seasons, special rules)
Location
County Ranking
Ranked #9 of 19 lakes in Keweenaw County
Nearby Lakes in Keweenaw County
More Wisconsin Lake Rankings
Other Grade A Lakes in Wisconsin
Mecosta County · Clarity: 12.8 ft
Benzie County · Clarity: 13.5 ft
Clare County · Clarity: 15 ft
Kalkaska County · Clarity: 16 ft
Gogebic County · Clarity: 18 ft
Iron County · Clarity: 16 ft
Mesotrophic Lakes in Wisconsin
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
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-07-26
Monitoring stations: 1