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Main St N over Thirty Mile Creek

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

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

Main St N over Thirty Mile Creek in Blaine 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 6 (satisfactory condition) on the 0-9 scale.
It was built in 1957, making it 68 years old at the 2025 inventory.
It carries about 546 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 57 of the 102 inventoried bridges in Blaine County rated fair (55.9%); 10 (9.8%) 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 88 ft
Location	Harlem
NBI structure number	S00241001+02531
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
US 2 over Main Irrigation Canal	1968	3,311	Good
Irr - US 2 over Milk River	1964	3,311	Poor
US 2 over Red Rock Creek Overflow	1942	2,919	Fair
US 2 over Drainage	1942	2,919	Fair
US 2 over Red Rock West Overflow	2020	2,732	Good
US 2 over Red Rock Coulee	2020	2,732	Good