Cottom Lane over Lemhi River
Lemhi County, Idaho · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Cottom Lane over Lemhi River in Lemhi County, Idaho, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1950 and reconstructed in 1968, making it 75 years old at the 2025 inventory.
- It carries about 70 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 40 of the 114 inventoried bridges in Lemhi County rated fair (35.1%); 9 (7.9%) 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 2023, 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 → (44.74911, -113.47578)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Timber stringer or multi-beam girder |
| Length | about 41 ft |
| Location | 7.2 S. 7.1 E. Lemhi |
| NBI structure number | 000000000032720 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | July 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | U: unknown foundation, not evaluated for scour |
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.