US Bridges

US 101 over Skokomish River

Fair

Mason County, Washington · 1.8 S JCT SR 106 · Structure no. 0001604A0000000

Built
1932
93 years old
Condition
Fair
inspected October 2023
Type
Truss - Thru
Steel
Length
405 ft
1 main span
Daily traffic
7,648
2023 count
Owner
State
State Highway Agency

About this bridge

US 101 over Skokomish River is a steel truss - thru carrying US 101 over Skokomish River in Mason County, Washington. It was built in 1932, so it is 93 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 7,648 vehicles a day, roughly 6% of them trucks, projected to reach 9,983 by 2039. The structure is 405 ft (123.4 m) long and 26 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

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CarriesUS 101
CrossesSkokomish River
Location1.8 S JCT SR 106
RouteU.S. Route 101
CountyMason County
StateWashington
Coordinates47.31047, -123.1765
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.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating43 US tons
Inventory rating26 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+4 approach)
Design loadH 15
Structure length405 ft (123.4 m)
Longest span240 ft (73.2 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deck16 ft (4.9 m)

Traffic and service

Average daily traffic7,648 (2023)
Projected traffic9,983 by 2039
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$6.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 101 over Skokomish River built?

It was built in 1932, making it 93 years old in 2025.

What condition is US 101 over Skokomish 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 2023.

How much traffic does US 101 over Skokomish River carry?

About 7,648 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is US 101 over Skokomish River?

The structure is 405 ft (123.4 m) long with a longest span of 240 ft (73.2 m) and a deck 26 ft wide.

Who owns US 101 over Skokomish River?

It is owned by the State Highway Agency.