Bridge conditions in Bannock County, Idaho
128 inventoried bridges · 6 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Bannock County tracks close to typical: 6 of its 128 inventoried bridges (4.7%) are rated poor, against a national rate of about 7%.
- 6 of the 128 bridges in Bannock County, Idaho, are rated in poor condition (4.7%) in the 2025 National Bridge Inventory, as of .
- 48 bridges (37.5%) are rated good and 74 (57.8%) fair.
- The median Bannock County bridge was built in 1971.
- The busiest poor-rated bridge is I 15 Nbl over Main Street Gs (built 1962), carrying about 7,750 vehicles a day.
Good 37.5% · Fair 57.8% · Poor 4.7% of 128 bridges
Bridges rated poor
Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 15 Nbl over Main Street Gs | 1962 | 7,750 | Poor |
| I 15 Sbl over Main Street Gs | 1962 | 7,750 | Poor |
| I 15 Nbl over I 15B;W.INKOM Ic | 1962 | 7,750 | Poor |
| STC7151;BENTON St over Portneuf River | 1969 | 2,800 | Poor |
| Stc 1757;MAIN St over Portneuf River | 1962 | 1,200 | Poor |
| E. Sublette Road over Portneuf Marsh Val.cnl | 1968 | 50 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 91 ;quinn Rd. over Uprr;quinn Road Op | 1986 | 22,500 | Good |
| I 15 Sbl over I 86 WB Ramp | 2024 | 19,250 | Good |
| I 15 Nbl over I 86 WB Ramp | 2023 | 19,250 | Good |
| I 15 Sbl over I 86 EB Ramp | 2024 | 19,250 | Good |
| I 15 Sbl over STP7041;CHUBBUCK Road | 2024 | 19,250 | Good |
| I 15 Nbl over I 15B;POCATELLO Creek Ic | 1999 | 19,000 | Fair |
| I 15 Sbl over I 15B;POCATELLO Creek Ic | 1998 | 19,000 | Fair |
| I 15 Nbl over Private Rd.;machine Pass | 1959 | 14,250 | Fair |
| I 15 Sbl over Private Rd.;machine Pass | 1959 | 14,250 | Fair |
| I 15 Nbl over Private Rd.;machine Pass | 1959 | 14,250 | Good |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
All of Idaho: Idaho bridge conditions by county · every download on the data page.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.