US Bridges

SH 3 over ST Maries River

Fair

Benewah County, Idaho · @ Santa Ncl · Structure no. 000000000010115

Built
1977
48 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
242 ft
3 main spans
Daily traffic
1,700
2023 count
Owner
State
State Highway Agency

About this bridge

SH 3 over ST Maries River is a prestressed concrete stringer/multi-beam or girder carrying SH 3 over ST Maries River in Benewah County, Idaho. It was built in 1977, so it is 48 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 1,700 vehicles a day, roughly 16% of them trucks, projected to reach 2,550 by 2042. The structure is 242 ft (73.8 m) long and 40 ft wide. If it were closed, the detour would be 18 mi (29 km).

Location

Open in Google Maps
CarriesSH 3
CrossesST Maries River
Location@ Santa Ncl
RouteState Highway 3
CountyBenewah County
StateIdaho
Coordinates47.15139, -116.45164
Functional classRural Minor Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
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 rating48 US tons
Inventory rating28 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length242 ft (73.8 m)
Longest span85 ft (25.9 m)
Deck width40 ft (12.1 m)
Roadway width37 ft (11.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,700 (2023)
Projected traffic2,550 by 2042
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18 mi (29 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 SH 3 over ST Maries River built?

It was built in 1977, making it 48 years old in 2025.

What condition is SH 3 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 October 2024.

How much traffic does SH 3 over ST Maries River carry?

About 1,700 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is SH 3 over ST Maries River?

The structure is 242 ft (73.8 m) long with a longest span of 85 ft (25.9 m) and a deck 40 ft wide.

Who owns SH 3 over ST Maries River?

It is owned by the State Highway Agency.