SH 29 over Eighteen Mile Creek
Lemhi County, Idaho · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SH 29 over Eighteen Mile Creek in Lemhi County, Idaho, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 8 (very good condition) on the 0-9 scale.
- It was built in 2019, making it 6 years old at the 2025 inventory.
- It carries about 180 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 65 of the 114 inventoried bridges in Lemhi County rated good (57.0%); 9 (7.9%) are rated poor.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (44.68322, -113.35506)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 8 | Very good condition |
| Superstructure | 8 | Very good condition |
| Substructure | 8 | Very good condition |
Bridge details
| Structure | Concrete frame |
| Length | about 32 ft |
| Location | 0.24 East of Leadore |
| NBI structure number | 000000000013453 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Idaho department of transportation.
Busiest bridges in Lemhi County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 93 over Salmon River;salmon Br. | 1926 | 7,300 | Poor |
| US 93 over Salmon River;carmen Br. | 1970 | 2,100 | Fair |
| US 93 over Carmen Creek | 1931 | 2,100 | Fair |
| US 93 over Tower Creek | 1931 | 2,100 | Fair |
| SH 28 over Lemhi River | 2001 | 1,700 | Good |
| SH 28 over Lemhi River | 2001 | 1,700 | Good |
All bridges nearby: Lemhi County, ID bridge conditions · every bridge in Lemhi County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.