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Willis Flat Road over So.fk.payette River

Boise County, Idaho · rated Fair in the 2025 National Bridge Inventory

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

Willis Flat Road over So.fk.payette River in Boise County, Idaho, 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 1959, making it 66 years old at the 2025 inventory.
It carries about 35 vehicles a day (traffic count year 1990).
It is one of 39 of the 89 inventoried bridges in Boise County rated fair (43.8%); 5 (5.6%) 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	Continuous steel stringer or multi-beam girder
Length	about 127 ft
Location	14 Mi East of Lowman Id
NBI structure number	040205000001201
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
SH 55 over McLEOD WAY	2024	10,500	Good
SH 55 over Payette River	2021	8,800	Good
SH 55 over Power Canal	1994	8,800	Good
SH 55 over Uprr;horseshoe Bend Op	1971	7,800	Fair
SH 55 over Payette River	1971	7,800	Fair
SH 55 over S.fk.payette River	1955	7,300	Fair