Saint Marys Lake
Saint Marys Lake in Calhoun County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Maximum depth: 38 ft. Surface area: 118.2 acres.
- Max depth
- 38 ft
- Area
- 118 acres
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Water clarity at Saint Marys Lake
Clear water. Across summers from 2018 to 2023, Saint Marys Lake averaged 3.68 m (12 ft) of visibility down into the water, so you can typically see several feet down in midsummer. This lake sits close to the line between clarity classes, so treat the label as approximate and the depth reading as the real number.
Nobody has taken a water sample here that we can find. Michigan's environmental agency measures clarity on lakes like this one from satellite images instead, which is why this page reports how clear the water is but carries no A–F grade.
Clear is not the same as clean. A lake can be easy to see through and still carry high nutrient levels, and a naturally tea-stained lake can be perfectly healthy. The A–F grade on other lakes is built from phosphorus and algae measured in a laboratory, and clarity alone cannot stand in for it.
The same satellite images put summer algae here at roughly 3.89 micrograms per litre. Estimating algae from orbit is far less exact than measuring clarity, so that figure is worth knowing and is not part of any rating.
Saint Marys Lake is a 118-acre lake in Calhoun County, Michigan with a maximum depth of 38 feet (14-foot average).
Source: EPA Water Quality Portal sampling records, EGLE, last sampled recent years. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Saint Marys Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near Saint Marys Lake
Compare lakeside cabins, hotels, and vacation rentals near Saint Marys Lake in Calhoun 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.
Top-rated places to stay near Saint Marys Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 38 ft |
| Average Depth | 14 ft |
| Surface Area | 118 acres |
| Shoreline Length | 1 mi |
Fishing Saint Marys Lake
Nearby Lakes in Calhoun County
Frequently asked questions about Saint Marys Lake
Where is Saint Marys Lake?
- Saint Marys Lake is a lake in Calhoun County, Michigan. LakeQuality has not rated this lake (UNRATED) — no in-situ water sample; this lake is rated for water clarity from satellite observations instead.
What is the water quality grade for Saint Marys Lake?
- Saint Marys Lake in Calhoun County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Maximum depth: 38 ft. Surface area: 118.2 acres.
Is Saint Marys Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Saint Marys Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Saint Marys Lake?
- Saint Marys Lake has a maximum depth of 38 feet and an average depth of 14 feet. The lake covers 118.2 acres.
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Where this data comes from
Measurements for Saint Marys Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.