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Bridge conditions in Caribou County, Idaho

45 inventoried bridges · 2 rated poor · 2025 National Bridge Inventory

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

The federal inventory lists 45 bridges in Caribou County: 12 rated good, 31 fair, and 2 poor.

2 of the 45 bridges in Caribou County, Idaho, are rated in poor condition (4.4%) in the 2025 National Bridge Inventory, as of August 20, 2026.
12 bridges (26.7%) are rated good and 31 (68.9%) fair.
The median Caribou County bridge was built in 1980.
The busiest poor-rated bridge is 8 Mile Road over Bear River (built 1972), carrying about 100 vehicles a day.

Good 26.7% · Fair 68.9% · Poor 4.4% of 45 bridges

Bridges rated poor

Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.

Bridge	Built	Vehicles/day	Condition
8 Mile Road over Bear River	1972	100	Poor
Chesterfield Res R over Chesterfield Canal	2005	50	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
SH 34 over Uprr;sodas 3RD E.st Op	1978	5,600	Fair
US 30 over UPRR; Soda Springs Op	1988	3,500	Fair
SH 34 over Bear River;grace Bridge	1974	2,200	Fair
SH 34 over North Extension Canal	1978	2,200	Fair
Blackfoot River Rd over Blackfoot River	1980	1,000	Good
SH 34 over Blackfoot River	1979	770	Fair
SH 34 over Little Blackfoot River	1979	770	Fair
SH 34 over Tincup Creek	1969	770	Good
SH 34 over Tincup Creek	1969	770	Good
SH 34 over Tincup Creek	2021	770	Good

Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.

All of Idaho: Idaho bridge conditions by county · every download on the data page.

Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.