Old US 10 over Big Ditch 051
Yellowstone County, Montana · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Old US 10 over Big Ditch 051 in Yellowstone County, Montana, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 3 (serious condition) on the 0-9 scale.
- It was built in 1932, making it 93 years old at the 2025 inventory.
- It carries about 2,489 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 7 of the 290 inventoried bridges in Yellowstone County rated poor (2.4%); 7 (2.4%) are rated poor.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (45.66842, -108.85797)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 6 | Satisfactory condition |
| Superstructure | 5 | Fair condition |
| Substructure | 3 | Serious condition |
Bridge details
| Structure | Concrete tee beam |
| Length | about 64 ft |
| Location | 4M W Laurel |
| NBI structure number | L56787001+02001 |
| Condition class | Poor |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Yellowstone County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I90 over MT Power RR Spur | 2023 | 29,488 | Good |
| I 90 over City County Drain Ditch | 1966 | 27,985 | Fair |
| King Ave W over Bbwa Canal | 1994 | 26,602 | Fair |
| Mullowney Ln over RR | 2007 | 23,980 | Good |
| Mullowney Ln over RR | 2007 | 23,980 | Fair |
| US 87 over Int Lockwood I 90 | 1966 | 23,199 | Fair |
All bridges nearby: Yellowstone County, MT bridge conditions · every bridge in Yellowstone County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.