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S 59 over Yellowstone River

Custer County, Montana · rated Fair in the 2025 National Bridge Inventory

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

S 59 over Yellowstone River in Custer County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
It was built in 1957, making it 68 years old at the 2025 inventory.
It carries about 2,949 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.
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.

Component ratings


Structure	Continuous steel girder and floorbeam
Length	about 976 ft
Location	Miles City
NBI structure number	P00018001+00921
Condition class	Fair

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

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
US 94 over Tongue River	2007	2,771	Fair