Big Island Lake is a mesotrophic lake in Schoolcraft County, Michigan. Water quality is graded C based on 1 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 5 documented fish species including Bluegill, Northern pike, and Pumpkinseed. Public access is available with 1 public boat landing. Compared to the 4 other monitored lakes in Schoolcraft County, Big Island Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2023-09-13. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 9.2 ft. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.2 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Big Island Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Island Lake in Schoolcraft 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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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Big Island Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -2.75 m/yr | 2 |
Recreation & Access
Water Temperature
Big Island Lake averages about 75°F at the surface in summer, usually warmest in Jul (about 75°F) and coldest in Sep (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 10 field readings (2011–2023) via the EPA Water Quality Portal. See the full Big Island Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of Big Island Lake, reaching a maximum surveyed depth of 35 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Michigan DNR.
County Ranking
Ranked #4 of 5 lakes in Schoolcraft County
Cleaner Lakes Within 30 Miles
Big Island Lake holds Grade C. 3 nearby lakes hold higher grades.
Nearby Lakes in Schoolcraft County
Explore Big Island Lake across LakeGrade
Fish species and top-graded lakes across Michigan
Species activity outlook by water temperature and season
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Moderate nutrients, good water quality
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Other Grade C Lakes in Michigan
Mesotrophic Lakes in Michigan
More records, surveys & data sources
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2023-09-13
Monitoring stations: 1