S 556-thompson R R over Thompson River
Flathead County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- S 556-thompson R R over Thompson River in Flathead County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1994, making it 31 years old at the 2025 inventory.
- It carries about 61 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 126 of the 204 inventoried bridges in Flathead County rated fair (61.8%); 9 (4.4%) 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 July 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 → (47.94095, -114.97509)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete tee beam |
| Length | about 60 ft |
| Location | 25M SW Marion |
| NBI structure number | S00556037+07091 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 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 Flathead County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 93 over Stillwater River | 1996 | 25,919 | Fair |
| N00109 over US 2 | 2016 | 22,752 | Good |
| Irr - US 2 over Flathead River | 1977 | 22,220 | Fair |
| US 93 Alternate over Foys Lake Road | 2021 | 19,966 | Good |
| US 93 Bypass over Ashley Creek | 2010 | 19,966 | Good |
| P00109 over Old Reserve Drive | 2016 | 19,964 | Good |
All bridges nearby: Flathead County, MT bridge conditions · every bridge in Flathead County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.