S 59 over Mill Creek-stockpass
Custer County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- S 59 over Mill Creek-stockpass in Custer County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1986, making it 39 years old at the 2025 inventory.
- It carries about 942 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 54 of the 71 inventoried bridges in Custer County rated fair (76.1%); 6 (8.5%) 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 April 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 → (46.30361, -105.75717)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Steel culvert |
| Length | about 32 ft |
| Location | 7M SE Miles City |
| NBI structure number | P00023009+05021 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | April 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Custer County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 94 over Lignite Creek | 1964 | 4,724 | Fair |
| I 94 over Coal Creek | 1963 | 4,724 | Fair |
| I 94 over Tongue River | 1961 | 4,707 | Fair |
| I 94 over Vehicle Pass | 1986 | 4,697 | Good |
| I 94 over Jones Creek-stockpass | 1962 | 4,393 | Fair |
| S 59 over Yellowstone River | 1957 | 2,949 | Fair |
All bridges nearby: Custer County, MT bridge conditions · every bridge in Custer County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.