Lost Coon Lake
Flathead County, MontanaView mapDirections
Montana DEQ publishes the water-quality measurements for Lost Coon Lake. Here is what has been measured.
- Limited data
Lost Coon Lake in Flathead County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Water clarity: 11.8 ft visibility.
Lost Coon Lake is a lake in Flathead County, Montana. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2023-10-07. Methodology: how these readings are compared.
What Lost Coon Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11.8 ft of visibility
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lost Coon 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 Lost Coon Lake
These are the measurements Montana DEQ publishes for Lost Coon Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 11.8 ft. TSI 42.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 42 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Lost Coon Lake
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Stays near Lost Coon Lake
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Top-rated places to stay near Lost Coon Lake
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Fishing Lost Coon Lake
Water Quality Trend: Worsening
Based on 12 years of monitoring (2012–2023).
Water clarity
Stable3 years
Phosphorus
Worsening+0.32 µg/L/yr11 years
Chlorophyll-a
Worsening+0.04 µg/L/yr12 years
Nearby Lakes in Flathead County
Frequently asked questions about Lost Coon Lake
Where is Lost Coon Lake?
- Lost Coon Lake is a lake in Flathead County, Montana. Its water-quality measurements are published by Montana DEQ and shown on this page as reported.
What is the water quality of Lost Coon Lake?
- Lost Coon Lake in Flathead County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Water clarity: 11.8 ft visibility.
Is Lost Coon Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Lost Coon Lake across LakeQuality
Planning a trip around Glacier?
Lost Coon Lake is about 32 miles from Glacier National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Glacier →More lakes in Montana
Other Lakes in Montana
Mesotrophic Lakes in Montana
Where this data comes from
21 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North American Lake Management Society
NALMS21 samples · 2020–2023
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.