I-5 over Stillaguamish R
FairSnohomish County, Washington · 0.7 N JCT SR 530 · Structure no. 0008791A0000000
- Built
- 1971
- 54 years old
- Condition
- Fair
- inspected April 2023
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 661 ft
- 4 main spans
- Daily traffic
- 45,626
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I-5 over Stillaguamish R is a steel continuous stringer/multi-beam or girder carrying I-5 over Stillaguamish R in Snohomish County, Washington. It was built in 1971, so it is 54 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 5 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 45,626 vehicles a day, roughly 8% of them trucks, projected to reach 65,795 by 2039. The structure is 661 ft (201.5 m) long and 55 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I-5 over Stillaguamish R built?
It was built in 1971, making it 54 years old in 2025.
What condition is I-5 over Stillaguamish R 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 April 2023.
How much traffic does I-5 over Stillaguamish R carry?
About 45,626 vehicles per day (2023 count), of which roughly 8% are trucks.
How long is I-5 over Stillaguamish R?
The structure is 661 ft (201.5 m) long with a longest span of 203 ft (61.9 m) and a deck 55 ft wide.
Who owns I-5 over Stillaguamish R?
It is owned by the State Highway Agency.