Saint Marys Lake
Lake County, Montana272 acresView mapDirections
No nutrient or algae sampling on record from Montana DEQ for this lake.
Saint Marys Lake in Lake County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Surface area: 272 acres.
Saint Marys Lake is a 272-acre lake in Lake County, Montana.
Source: EPA Water Quality Portal sampling records, Montana DEQ. Methodology: how these readings are compared.
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Saint Marys Lake is safe to swim in today is a call for the Montana Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Saint Marys Lake
These are the measurements Montana DEQ publishes for Saint Marys Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. TSI undefined.
Ask about Saint Marys Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
272 acres
Shoreline
4.1 mi
No bathymetric survey has been published for Saint Marys Lake, so its depth is not documented here.
Stays via Stay22
Stays near Saint Marys Lake
Compare lakeside cabins, hotels, and vacation rentals near Saint Marys Lake in Lake County, Montana — 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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Frequently asked questions about Saint Marys Lake
Where is Saint Marys Lake?
- Saint Marys Lake is a lake in Lake County, Montana. Its water-quality measurements are published by Montana DEQ and shown on this page as reported.
What is the water quality of Saint Marys Lake?
- Saint Marys Lake in Lake County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Surface area: 272 acres.
Is Saint Marys Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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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.