Long Lake
Cass County, WisconsinLimited DataMesotrophic
Long Lake is a mesotrophic lake in Cass County, MI. Water quality is graded B based on 1 sampling years through 2022. The lake supports 25 documented fish species including Blacknose shiner, Blackside darter, and Blackstripe topminnow. Compared to the 22 other monitored lakes in Cass County, Long Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2022-09-16. Grade methodology: LakeGrade methodology.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 10.5 ft. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 43 | 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 Long Lake (14-day solunar calendar)
→ Is it safe to eat fish from Long Lake? (mercury & PFAS guide)
→ Long Lake fishing regulations (limits, seasons, special rules)
Location
County Ranking
Ranked #4 of 23 lakes in Cass County
Cleaner Lakes Within 30 Miles
Long Lake holds Grade B. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Cass County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Lapeer County · Clarity: 9.5 ft
Livingston County · Clarity: 13 ft
Manistee County · Clarity: 11 ft
Lake County · Clarity: 14 ft
Genesee County · Clarity: 10 ft
Lake County · Clarity: 8 ft
Mesotrophic Lakes in Wisconsin
EPA Impairment Status
Long Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MI040500011303-06 · 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: 2022-09-16
Monitoring stations: 1