Estimated average retail price of regular-grade gasoline across all formulations in EIA's Rocky Mountain region, including taxes. The region contains Colorado, Idaho, Montana, Utah, and Wyoming.
Idaho compared with the U.S.
Regular gasoline price- Idaho
- $4.314/gal
- United States
- $4.157/gal
The Rocky Mountain average was $0.157 per gallon higher, or about 3.8% above the U.S. average.
Both figures are EIA weekly retail estimates for regular gasoline, including taxes, for the week of September 7, 2026. The Idaho-side figure is the Rocky Mountain regional average, not an Idaho statewide estimate. Recent EIA observations
- Prior week
- $4.266/gal
- Weekly change
- +4.8¢
- One year earlier
- $3.240/gal
- Change from one year earlier
- +107.4¢
How it was measured: FactVote uses EIA’s Rocky Mountain series, the smallest current EIA retail region that includes Idaho. Changes are calculated from the published August 31, 2026 (prior week), and September 8, 2025 (52 weeks earlier), observations.
Keep in mind- EIA does not publish a current Idaho statewide weekly gasoline-price series. This Rocky Mountain regional estimate should not be read as Idaho’s statewide average.
- The regional average combines Colorado, Idaho, Montana, Utah, and Wyoming, and does not represent the price at every station or in every Idaho community.
- Prices are nominal and not adjusted for inflation or seasonal patterns. Weekly estimates can be revised and can differ from monthly averages.
- Price changes alone do not establish the effect of any bill, official, or government action.
Context only. This number does not affect candidate matches or rankings.