S 323 over Little Missouri River
Carter County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- S 323 over Little Missouri River in Carter County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1983, making it 42 years old at the 2025 inventory.
- It carries about 216 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 27 of the 42 inventoried bridges in Carter County rated fair (64.3%); 2 (4.8%) 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 August 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 → (45.19897, -104.29719)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 8 | 8 | Very good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 142 ft |
| Location | 15M NE Alzada |
| NBI structure number | S00323056+05001 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | August 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 Carter County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 212 over Drainage | 1965 | 2,642 | Fair |
| US 212 over Thompson Creek | 1965 | 2,642 | Fair |
| US 212 over Little Missouri River | 1965 | 2,642 | Fair |
| US 212 over Willow Creek | 1955 | 2,285 | Fair |
| Chicago AVE over Russell Creek | 2019 | 480 | Good |
| Mormon Ave over Russell Creek 035 | 1940 | 480 | Fair |
All bridges nearby: Carter County, MT bridge conditions · every bridge in Carter County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.