Upper Hamlin Lake
Mason County, MichiganView mapDirections
EGLE publishes the water-quality measurements for Upper Hamlin Lake. Here is what has been measured.
- Mesotrophic
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Answers come straight from the public measurements and survey records on this page.
Upper Hamlin Lake in Mason County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 29 µg/L. Chlorophyll-a (algae): 6.2 µg/L.
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Upper Hamlin Lake is a mesotrophic lake in Mason County, Michigan. Water clarity is improving over recent sampling years. The lake supports 6 documented fish species including Blackchin shiner, Bluntnose minnow, and Mimic shiner. Compared to the 3 other monitored lakes in Mason County, Upper Hamlin Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-09-12. Grade methodology: LakeQuality methodology.
What Upper Hamlin Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
Swimming conditions
Readings onlyModerate algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Upper Hamlin Lake is safe to swim in today is a call for the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Upper Hamlin Lake
These are the measurements EGLE publishes for Upper Hamlin Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 6 ft. Phosphorus 29 µg/L. Chlorophyll-a 6.2 µg/L. TSI 51.
| Metric | Value | EPA condition class |
|---|---|---|
| Water Clarity (Secchi Depth) | 6 ft | Measured, not scored |
| Phosphorus | 29 µg/L | Fair |
| Chlorophyll-a (Algae) | 6.2 µg/L | Good |
| Trophic State Index (TSI) | 51 | Mesotrophic |
Moderate nutrients, good water quality
Fish Species
Click a species to see every lake where it is documented.
Fishing Upper Hamlin Lake
Water Quality Trend: → Stable
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.222 m/yr | 7 |
| Phosphorus | → Stable | +0.27 µg/L/yr | 7 |
| Chlorophyll-a | ↓ Declining | +0.9 µg/L/yr | 7 |
Nearby Lakes in Mason County
Frequently asked questions about Upper Hamlin Lake
Where is Upper Hamlin Lake?
- Upper Hamlin Lake is a lake in Mason County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Upper Hamlin Lake?
- Upper Hamlin Lake in Mason County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 29 µg/L. Chlorophyll-a (algae): 6.2 µg/L.
Is Upper Hamlin Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What fish are in Upper Hamlin Lake?
- Fish species found in Upper Hamlin Lake include Blackchin shiner, Bluntnose minnow, Mimic shiner, Sand shiner, Western banded killifish, Yellow perch. Upper Hamlin Lake is located in Mason County, Michigan.
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Where this data comes from
184 measurements from 1 monitoring station, 2016–2023. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS184 samples · 2016–2023
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.