Fennon Slough
Fennon Slough in Flathead County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 209 acres.
- Area
- 209 acres
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Why Fennon Slough has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Fennon Slough, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. 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.
Fennon Slough is a 209-acre lake in Flathead County, Montana.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled recent years. Grade methodology: LakeQuality methodology.
Watch Fennon Slough water quality
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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 Fennon Slough
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 Fennon Slough
Compare lakeside cabins, hotels, and vacation rentals near Fennon Slough in Flathead 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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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 209 acres |
No bathymetric survey has been published for Fennon Slough, so its depth is not documented here.
Fishing Fennon Slough
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Frequently asked questions about Fennon Slough
Where is Fennon Slough?
- Fennon Slough is a lake in Flathead County, Montana. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Fennon Slough?
- Fennon Slough in Flathead County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 209 acres.
Is Fennon Slough safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Fennon Slough is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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Where this data comes from
Measurements for Fennon Slough come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.