Bridge conditions in Boise County, Idaho
89 inventoried bridges · 5 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
5 of the 89 bridges the federal inventory lists in Boise County are rated poor; the rest split 45 good and 39 fair.
- 5 of the 89 bridges in Boise County, Idaho, are rated in poor condition (5.6%) in the 2025 National Bridge Inventory, as of .
- 45 bridges (50.6%) are rated good and 39 (43.8%) fair.
- The median Boise County bridge was built in 1979.
- The busiest poor-rated bridge is Anderson Creek Rd over Anderson Creek (built 1983), carrying about 100 vehicles a day.
Good 50.6% · Fair 43.8% · Poor 5.6% of 89 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 |
|---|---|---|---|
| Anderson Creek Rd over Anderson Creek | 1983 | 100 | Poor |
| Boulder Creek Road over Mores Creek | 1982 | 50 | Poor |
| Cottonwd-bannock over Mores Creek | 1962 | 30 | Poor |
| Shafer Creek Road over Shafer Creek | 1914 | 20 | Poor |
| Avelene Ck. Road over Grimes Creek | 1954 | 20 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SH 55 over McLEOD WAY | 2024 | 10,500 | Good |
| SH 55 over Payette River | 2021 | 8,800 | Good |
| SH 55 over Power Canal | 1994 | 8,800 | Good |
| SH 55 over Uprr;horseshoe Bend Op | 1971 | 7,800 | Fair |
| SH 55 over Payette River | 1971 | 7,800 | Fair |
| SH 55 over S.fk.payette River | 1955 | 7,300 | Fair |
| SH 55 over N.fk.payette River | 1984 | 4,700 | Fair |
| SH 21 over Wildlife Crossing | 2010 | 3,500 | Good |
| SH 21 over Mores CR; Dunnigan CR | 2008 | 2,900 | Good |
| SH 21 over Mores Cr.;spencers Cabin | 1995 | 2,900 | 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.