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US 87 over Boyd Creek

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

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

US 87 over Boyd Creek in Fergus County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
It was built in 1942, making it 83 years old at the 2025 inventory.
It carries about 2,831 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 97 of the 158 inventoried bridges in Fergus County rated fair (61.4%); 9 (5.7%) 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	Timber stringer or multi-beam girder
Length	about 57 ft
Location	1M E Lewistown
NBI structure number	P00057084+02521
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
US 87-e Main St over Mill Ditch	1922	8,747	Fair
US 87-w Main St over Big Spring Creek	1962	5,357	Fair
US 191-1st Ave N over Big Spring Creek	1960	5,189	Fair
US 191-kendall Rd over Big Spring Creek	1976	2,663	Fair
US 87 over Beaver Creek	2009	2,589	Good
US 87 over Cottonwood Creek	2009	2,589	Fair