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S 89 over Blacktail Creek

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

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

S 89 over Blacktail Creek in Beaverhead County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
It was built in 1983, making it 42 years old at the 2025 inventory.
It carries about 1,804 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 150 of the 227 inventoried bridges in Beaverhead County rated fair (66.1%); 24 (10.6%) 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	Prestressed concrete stringer or multi-beam girder
Length	about 98 ft
Location	South Dillon
NBI structure number	P00089000+03311
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
S 89 over Local-blacktail Cr-rr	1974	4,241	Fair
S 89 over Int North Dillon I 15	1973	4,241	Fair
I 15 over Drainage Irr Ditch	1973	3,915	Fair
I 15 over Birch Creek	1973	3,852	Fair
I 15 over Int Jackson-hwy 278	1982	2,863	Fair
I 15 over Int Jackson-hwy 278	1982	2,863	Good