US 20 over Big Lost River
Butte County, Idaho · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 20 over Big Lost River in Butte County, Idaho, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1977, making it 48 years old at the 2025 inventory.
- It carries about 2,700 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 9 of the 32 inventoried bridges in Butte County rated good (28.1%); 1 (3.1%) 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 → (43.54864, -113.00694)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 8 | Very good condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 61 ft |
| Location | 16.4 E. Arco |
| NBI structure number | 000000000013200 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Idaho department of transportation.
Busiest bridges in Butte County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 20 over Inl Central Connector | 1993 | 4,400 | Fair |
| US 93 over Arco Canal | 1962 | 2,600 | Good |
| US 93 over Spring Creek | 1962 | 2,600 | Good |
| US 93 over Big Lost River | 1962 | 2,600 | Fair |
| US 93 over Big Lost River | 1958 | 2,300 | Fair |
| Stc 6749;2500N over Big Lost River | 1926 | 500 | Fair |
All bridges nearby: Butte County, ID bridge conditions · every bridge in Butte County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.