Murphy Lake
Lincoln County, MontanaView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Limited data
Murphy Lake in Lincoln County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15 ft visibility.
- Clarity
- 15 ft
- Trend
- → Stable
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Stays near Murphy Lake
Compare lakeside cabins, hotels, and vacation rentals near Murphy Lake in Lincoln 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.
Top-rated places to stay near Murphy Lake
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Watch Murphy Lake’s letter
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Why Murphy Lake has no grade
Murphy Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Murphy Lake is Not Rated — not an F. Its 15-foot median from 21 readings collected 2020–2023 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by Montana DEQ and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Murphy Lake is a lake in Lincoln County, Montana. Water clarity is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled 2023-07-18. Grade methodology: LakeQuality methodology.
What Murphy Lake is good for
From access and monitoring records, not editorial picks.
- Clear water15 ft of visibility
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Check local advisories before you swim.
Water quality measurements for Murphy Lake
These readings exist but are not enough for an A–F grade — see why.
Crystal clear, you can see 15 ft down. TSI 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Fishing Murphy Lake
Water Quality Trend: → Stable
Based on 11 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.721 m/yr | 3 |
| Phosphorus | ↓ Declining | +0.15 µg/L/yr | 10 |
| Chlorophyll-a | → Stable | 0 µg/L/yr | 11 |
Graded lakes near Murphy Lake
Murphy Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Lincoln County
Frequently asked questions about Murphy Lake
Where is Murphy Lake?
- Murphy Lake is a lake in Lincoln County, Montana. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.
What is the water quality grade for Murphy Lake?
- Murphy Lake in Lincoln County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15 ft visibility.
Is Murphy Lake safe to swim in?
- The letter is not a swimming clearance. Check local advisories before you swim.
Explore Murphy Lake across LakeQuality
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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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.