Skull Canyon Road over Birch Creek
Clark County, Idaho · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Skull Canyon Road over Birch Creek in Clark County, Idaho, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 2001, making it 24 years old at the 2025 inventory.
- It carries about 10 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 25 of the 39 inventoried bridges in Clark County rated fair (64.1%); 5 (12.8%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated July 2024, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (44.16019, -112.91225)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Timber stringer or multi-beam girder |
| Length | about 21 ft |
| Location | 0.5 N. Blue Dome |
| NBI structure number | 000000000031623 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | July 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 4: foundations stable, field review says exposed foundations need protection |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Idaho department of transportation.
Busiest bridges in Clark County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 15 over Frontage Road | 1965 | 3,700 | Fair |
| I 15 over Beaver Creek | 1969 | 3,500 | Fair |
| I 15 over Frontage Road Gs | 1969 | 3,500 | Fair |
| I 15 over Beaver Creek | 1963 | 3,400 | Fair |
| I 15 Nbl & Sbl over Beaver Creek;s.dubois Br | 1965 | 3,400 | Fair |
| I 15 Nbl over Spencer Road Ic | 1969 | 1,850 | Fair |
All bridges nearby: Clark County, ID bridge conditions · every bridge in Clark County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.