US Bridges

US 97 over Okanogan River

Fair

Okanogan County, Washington · 3.6 N JCT SR 173 · Structure no. 000000LX0000000

Built
1950
75 years old
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
458 ft
6 main spans
Daily traffic
4,504
2023 count
Owner
Federal
Corps of Engineers (Civil)

About this bridge

US 97 over Okanogan River is a steel stringer/multi-beam or girder carrying US 97 over Okanogan River in Okanogan County, Washington. It was built in 1950, so it is 75 years old, older than the Washington average of 49.8 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 4,504 vehicles a day, roughly 15% of them trucks, projected to reach 5,711 by 2039. The structure is 458 ft (139.6 m) long and 33 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesUS 97
CrossesOkanogan River
Location3.6 N JCT SR 173
RouteU.S. Route 97
CountyOkanogan County
StateWashington
Coordinates48.10278, -119.71042
Functional classRural Principal Arterial - Other

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55 US tons
Inventory rating33 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length458 ft (139.6 m)
Longest span100 ft (30.5 m)
Deck width33 ft (10.1 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,504 (2023)
Projected traffic5,711 by 2039
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCorps of Engineers (Civil)
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$8.3 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 97 over Okanogan River built?

It was built in 1950, making it 75 years old in 2025.

What condition is US 97 over Okanogan 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 March 2023.

How much traffic does US 97 over Okanogan River carry?

About 4,504 vehicles per day (2023 count), of which roughly 15% are trucks.

How long is US 97 over Okanogan River?

The structure is 458 ft (139.6 m) long with a longest span of 100 ft (30.5 m) and a deck 33 ft wide.

Who owns US 97 over Okanogan River?

It is owned by the Corps of Engineers (Civil) and maintained by the State Highway Agency.