S 340 over Plum Coulee Creek

Prairie County, Montana · rated Good in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

• S 340 over Plum Coulee Creek in Prairie County, Montana, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
• Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
• It was built in 2020, making it 5 years old at the 2025 inventory.
• It carries about 162 vehicles a day (traffic count year 2023).
• Its listed owner is the state highway agency.
• It is one of 4 of the 46 inventoried bridges in Prairie County rated good (8.7%); 5 (10.9%) 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 January 2025, on a 24-month routine inspection cycle.
• 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 → (46.82806, -105.10517)

Component ratings

Bridge details

Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.

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Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.