US Bridges

Iron Creek Road over Salmon River;iron Ck Br

Fair

Lemhi County, Idaho · 20 S. Salmon · Structure no. 000000000032665

Built
1965
60 years old
Condition
Fair
inspected April 2024
Type
Slab
Concrete Continuous
Length
230 ft
5 main spans
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

Iron Creek Road over Salmon River;iron Ck Br is a concrete continuous slab carrying Iron Creek Road over Salmon River;iron Ck Br in Lemhi County, Idaho. It was built in 1965, so it is 60 years old, older than the Idaho average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 50 vehicles a day, roughly 10% of them trucks, projected to reach 75 by 2039. The structure is 230 ft (70.1 m) long and 16 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

CarriesIron Creek Road
CrossesSalmon River;iron Ck Br
Location20 S. Salmon
RouteCounty Highway 0
StateIdaho
Coordinates44.88489, -113.97283
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating65 US tons
Inventory rating39 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadH 20
Structure length230 ft (70.1 m)
Longest span50 ft (15.2 m)
Deck width16 ft (4.9 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2023)
Projected traffic75 by 2039
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.8 million (2019 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Iron Creek Road over Salmon River;iron Ck Br built?

It was built in 1965, making it 60 years old in 2025.

What condition is Iron Creek Road over Salmon River;iron Ck Br in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in April 2024.

How much traffic does Iron Creek Road over Salmon River;iron Ck Br carry?

About 50 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Iron Creek Road over Salmon River;iron Ck Br?

The structure is 230 ft (70.1 m) long with a longest span of 50 ft (15.2 m) and a deck 16 ft wide.

Who owns Iron Creek Road over Salmon River;iron Ck Br?

It is owned by the County Highway Agency.