US Bridges

US 101 over South Nemah River

Fair

Pacific County, Washington · 3.6 N JCT SR 4 · Structure no. 000000NB0000000

Built
1957
68 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
48 ft
3 main spans
Daily traffic
2,815
2023 count
Owner
State
State Highway Agency

About this bridge

US 101 over South Nemah River is a steel continuous stringer/multi-beam or girder carrying US 101 over South Nemah River in Pacific County, Washington. It was built in 1957, so it is 68 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 2,815 vehicles a day, roughly 8% of them trucks, projected to reach 3,300 by 2039. The structure is 48 ft (14.6 m) long and 30 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesUS 101
CrossesSouth Nemah River
Location3.6 N JCT SR 4
RouteU.S. Route 101
CountyPacific County
StateWashington
Coordinates46.47519, -123.88497
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.9 US tons
Inventory rating23 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckWood or timber
Main spans3
Design loadHS 15
Structure length48 ft (14.6 m)
Longest span37 ft (11.3 m)
Deck width30 ft (9.2 m)
Roadway width29 ft (8.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,815 (2023)
Projected traffic3,300 by 2039
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
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$866,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 101 over South Nemah River built?

It was built in 1957, making it 68 years old in 2025.

What condition is US 101 over South Nemah 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 August 2023.

How much traffic does US 101 over South Nemah River carry?

About 2,815 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is US 101 over South Nemah River?

The structure is 48 ft (14.6 m) long with a longest span of 37 ft (11.3 m) and a deck 30 ft wide.

Who owns US 101 over South Nemah River?

It is owned by the State Highway Agency.