Reservoir · Idaho · United States · BOR RISE
Island Park Reservoir
Island Park Reservoir and Dam
15.9% full
Capacity
157.45 hm³
Volume stored
25 hm³
Coordinates
44.419°N, 111.398°W
Last updated
2026-09-30
Current fill
15.9%vs 7 days ago
+2.1%gaining
vs 1 year ago
-19.8%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. 44.419, -111.398 · Open in Google Maps
About Island Park Reservoir
As of September 30, 2026, Island Park Reservoir is filled to 15.9% of its total capacity, holding roughly 25 hm³ of water out of a maximum 157 hm³. At this level the reservoir is critically low.
Over the most recent week on record the fill level has risen by 2.1 percentage points, and it is 19.8 points below its level on the same date a year earlier.
Across the readings we hold for Island Park Reservoir — 2190 data points between October 2, 2021 and September 30, 2026 — the level has ranged from a low of 13.0% (September 19, 2026) to a high of 105.0% (May 19, 2022). On average the reservoir is fullest around May and at its lowest around September.
It is operated by BOR primarily for multiple purposes. It lies within the Idaho basin at 44.419°N, 111.398°W.
Key facts
- Current fill level
- 15.9%
- Water stored
- 25 hm³
- Total capacity
- 157 hm³
- 7-day change
- ▲ 2.1 pts
- Year-on-year
- ▼ 19.8 pts
- Primary use
- Multipurpose
- River basin
- Idaho
- Operator
- BOR
- Coordinates
- 44.419°N, 111.398°W
- Last updated
- September 30, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 30 Sep 2026 | 15.9% | 25 |
| 29 Sep 2026 | 15.6% | 25 |
| 28 Sep 2026 | 15.3% | 24 |
| 27 Sep 2026 | 15.0% | 24 |
| 26 Sep 2026 | 14.7% | 23 |
| 25 Sep 2026 | 14.4% | 23 |
| 24 Sep 2026 | 14.1% | 22 |
| 23 Sep 2026 | 13.8% | 22 |
| 22 Sep 2026 | 13.5% | 21 |
| 21 Sep 2026 | 13.2% | 21 |
| 20 Sep 2026 | 13.0% | 21 |
| 19 Sep 2026 | 13.0% | 21 |