S 21-s Main St over Pondera Coulee
Pondera County, Montana · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- S 21-s Main St over Pondera Coulee in Pondera County, Montana, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
- It was built in 1934 and reconstructed in 1989, making it 91 years old at the 2025 inventory.
- It carries about 1,245 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 49 of the 96 inventoried bridges in Pondera County rated good (51.0%); 4 (4.2%) 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 → (48.16372, -111.95012)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 7 | Good condition |
Bridge details
| Structure | Steel culvert |
| Length | about 37 ft |
| Location | Conrad By Fleet Supply |
| NBI structure number | P00021003+08001 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Pondera County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 15 over S Pondera Coulee | 1964 | 3,248 | Fair |
| I 15 over RR | 1972 | 1,727 | Good |
| I 15 over RR | 1972 | 1,727 | Good |
| I 15 over Dry Fork Marias River | 1972 | 1,727 | Good |
| I 15 over Dry Fork Marias River | 1972 | 1,727 | Good |
| S 21 over RR | 1972 | 1,725 | Good |
All bridges nearby: Pondera County, MT bridge conditions · every bridge in Pondera County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.