US Bridges

Wallowa Loop Road over Imnaha River

Fair

Wallowa County, Oregon · Ollokot Campground · Structure no. 061604000001032

Built
1965
60 years old
Condition
Fair
inspected July 2023
Type
Frame
Concrete Continuous
Length
97 ft
3 main spans
Daily traffic
225
2001 count
Owner
Federal
U.S. Forest Service

About this bridge

Wallowa Loop Road over Imnaha River is a concrete continuous frame carrying Wallowa Loop Road over Imnaha River in Wallowa County, Oregon. It was built in 1965, so it is 60 years old, older than the Oregon average of 49.9 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 225 vehicles a day, roughly 10% of them trucks, projected to reach 337 by 2045. The structure is 97 ft (29.6 m) long and 31 ft wide. If it were closed, the detour would be 620.7 mi (999 km).

Location

Open in Google Maps
CarriesWallowa Loop Road
CrossesImnaha River
LocationOllokot Campground
RouteFederal Lands Road 39000
CountyWallowa County
StateOregon
Coordinates45.15099, -116.87766
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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71.1 US tons
Inventory rating50 US tons

Structure

Structure typeFrame
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadOther
Structure length97 ft (29.6 m)
Longest span65 ft (19.8 m)
Deck width31 ft (9.3 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic225 (2001)
Projected traffic337 by 2045
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed620.7 mi (999 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Wallowa Loop Road over Imnaha River built?

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

What condition is Wallowa Loop Road over Imnaha 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 July 2023.

How much traffic does Wallowa Loop Road over Imnaha River carry?

About 225 vehicles per day (2001 count), of which roughly 10% are trucks.

How long is Wallowa Loop Road over Imnaha River?

The structure is 97 ft (29.6 m) long with a longest span of 65 ft (19.8 m) and a deck 31 ft wide.

Who owns Wallowa Loop Road over Imnaha River?

It is owned by the U.S. Forest Service.