I-5 over Nisqually River
FairThurston County, Washington · 2.9 N JCT SR 510 · Structure no. 0008116A0000000
- Built
- 1967
- 58 years old
- Condition
- Fair
- inspected April 2023
- Type
- Truss - Thru
- Steel
- Length
- 431 ft
- 1 main span
- Daily traffic
- 62,815
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I-5 over Nisqually River is a steel truss - thru carrying I-5 over Nisqually River in Thurston County, Washington. It was built in 1967, so it is 58 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 62,815 vehicles a day, roughly 12% of them trucks, projected to reach 90,182 by 2039. The structure is 431 ft (131.4 m) long and 52 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I-5 over Nisqually River built?
It was built in 1967, making it 58 years old in 2025.
What condition is I-5 over Nisqually 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 April 2023.
How much traffic does I-5 over Nisqually River carry?
About 62,815 vehicles per day (2023 count), of which roughly 12% are trucks.
How long is I-5 over Nisqually River?
The structure is 431 ft (131.4 m) long with a longest span of 322 ft (98.1 m) and a deck 52 ft wide.
Who owns I-5 over Nisqually River?
It is owned by the State Highway Agency.