Irr Bia Rte 1 over Birch Creek
Pondera County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr Bia Rte 1 over Birch Creek in Pondera County, Montana, 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 1966, making it 59 years old at the 2025 inventory.
- It carries about 700 vehicles a day (traffic count year 2023).
- It is one of 43 of the 96 inventoried bridges in Pondera County rated fair (44.8%); 4 (4.2%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 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 → (48.23306, -112.73425)
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 | Prestressed concrete stringer or multi-beam girder |
| Length | about 200 ft |
| Location | 13 Km SE of Heart Butte |
| NBI structure number | 00000000000C105 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
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.