US Bridges

Old County Road over St. Maries River

Fair

Benewah County, Idaho · 0.4 S. Fernwood · Structure no. 000000000030041

Built
2015
10 years old
Condition
Fair
inspected September 2023
Type
Tee Beam
Prestressed Concrete
Length
271 ft
3 main spans
Daily traffic
350
2023 count
Owner
County
County Highway Agency

About this bridge

Old County Road over St. Maries River is a prestressed concrete tee beam carrying Old County Road over St. Maries River in Benewah County, Idaho. It was built in 2015, so it is 10 years old, younger 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 350 vehicles a day, roughly 13% of them trucks, projected to reach 525 by 2042. The structure is 271 ft (82.6 m) long and 32 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesOld County Road
CrossesSt. Maries River
Location0.4 S. Fernwood
RouteCounty Highway 0
CountyBenewah County
StateIdaho
Coordinates47.10506, -116.39297
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52.5 US tons
Inventory rating36.8 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadHL 93
Structure length271 ft (82.6 m)
Longest span160 ft (48.8 m)
Deck width32 ft (9.7 m)
Roadway width29 ft (8.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic350 (2023)
Projected traffic525 by 2042
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Old County Road over St. Maries River built?

It was built in 2015, making it 10 years old in 2025.

What condition is Old County Road over St. Maries River 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 September 2023.

How much traffic does Old County Road over St. Maries River carry?

About 350 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is Old County Road over St. Maries River?

The structure is 271 ft (82.6 m) long with a longest span of 160 ft (48.8 m) and a deck 32 ft wide.

Who owns Old County Road over St. Maries River?

It is owned by the County Highway Agency.