Reservoir · Idaho · United States · BOR RISE
American Falls Reservoir
American Falls Reservoir and Dam
5.4% full
Capacity
2,061.52 hm³
Volume stored
111 hm³
Coordinates
42.779°N, 112.879°W
Last updated
2026-09-30
Current fill
5.4%vs 7 days ago
+1.6%gaining
vs 1 year ago
+2.4%year-over-year
7-day trend
↑rising
Data source: BOR RISE — US Bureau of Reclamation — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-09-30.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 42.779, -112.879 · Open in Google Maps
About American Falls Reservoir
As of September 30, 2026, American Falls Reservoir is filled to 5.4% of its total capacity, holding roughly 111 hm³ of water out of a maximum 2,062 hm³. At this level the reservoir is critically low.
Over the most recent week on record the fill level has risen by 1.6 percentage points, and it is 2.4 points above its level on the same date a year earlier.
Across the readings we hold for American Falls Reservoir — 2188 data points between October 2, 2021 and September 30, 2026 — the level has ranged from a low of 3.0% (September 30, 2025) to a high of 100.2% (May 24, 2024). On average the reservoir is fullest around April and at its lowest around September.
It is operated by BOR primarily for multiple purposes. It lies within the Idaho basin at 42.779°N, 112.879°W.
Key facts
- Current fill level
- 5.4%
- Water stored
- 111 hm³
- Total capacity
- 2,062 hm³
- 7-day change
- ▲ 1.6 pts
- Year-on-year
- ▲ 2.4 pts
- Primary use
- Multipurpose
- River basin
- Idaho
- Operator
- BOR
- Coordinates
- 42.779°N, 112.879°W
- Last updated
- September 30, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 30 Sep 2026 | 5.4% | 111 |
| 29 Sep 2026 | 5.3% | 110 |
| 28 Sep 2026 | 5.1% | 105 |
| 27 Sep 2026 | 4.7% | 98 |
| 26 Sep 2026 | 4.6% | 95 |
| 25 Sep 2026 | 4.2% | 86 |
| 24 Sep 2026 | 4.0% | 83 |
| 23 Sep 2026 | 3.8% | 78 |
| 22 Sep 2026 | 3.6% | 74 |
| 21 Sep 2026 | 3.5% | 71 |
| 20 Sep 2026 | 3.4% | 71 |
| 19 Sep 2026 | 3.4% | 70 |