
Fremont County Lake Quality
Idaho, 18 lakes, measured by Idaho DEQ
There are 18 monitored lakes in Fremont County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 2 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. Phosphorus and algae readings vary widely across Fremont County; the per-lake pages below carry the numbers.
The county's lakes lean shallow, which makes the readings sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest measured lake is Island Park Lake.
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Quick Answers for Fremont County
Planning a trip? Check special fishing regulations for Island Park Lake — or check the official Idaho fishing regulations.
All Lakes in Fremont County
18 lakes · 2 ranked on readings, 16 without enough sampling2 lakes ranked on readings · 16 without enough sampling, hidden
| # | Lake | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|
| 1 | Island Park LakeFremont | 9.8 ft | 24 µg/L | 11.8 µg/L | No recent samples | ✓ Public |
| 2 | Island Pk ReservoirFremont | 2.3 ft | 56 µg/L | 9.8 µg/L | No recent samples | Not recorded |
| Henry'S Lake @ Boat RampFremont | No recent samples | 11 µg/L | 1.5 µg/L | No recent samples | ✓ Public | |
| Henrys LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | ✓ Public | |
| Ashton ReservoirFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Horseshoe LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Robinson LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Beaver PondFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Fish PondFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Swan LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Silver LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Golden LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Sand Creek ReservoirFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Upper Arcadia ReservoirFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Lower Arcadia ReservoirFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Lemon LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Egin LakesFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Quayles LakeFremont | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.
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Source: the Idaho Department of Environmental Quality. See data sources.