NE Marymoor Way over Sammamish Slough
FairKing County, Washington · 0.5 MI S of SR-520 · Structure no. 080543000000000
- Built
- 1963
- 62 years old
- Condition
- Fair
- inspected June 2024
- Type
- Tee Beam
- Concrete
- Length
- 117 ft
- 3 main spans
- Daily traffic
- 1,600
- 2020 count
- Owner
- Local
- Local Park, Forest, or Reservation Agency
About this bridge
NE Marymoor Way over Sammamish Slough is a concrete tee beam carrying NE Marymoor Way over Sammamish Slough in King County, Washington. It was built in 1963, so it is 62 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 1,600 vehicles a day, roughly 5% of them trucks, projected to reach 1,850 by 2040. The structure is 117 ft (35.7 m) long and 36 ft wide. If it were closed, the detour would be 3.1 mi (5 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 | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was NE Marymoor Way over Sammamish Slough built?
It was built in 1963, making it 62 years old in 2025.
What condition is NE Marymoor Way over Sammamish Slough 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 June 2024.
How much traffic does NE Marymoor Way over Sammamish Slough carry?
About 1,600 vehicles per day (2020 count), of which roughly 5% are trucks.
How long is NE Marymoor Way over Sammamish Slough?
The structure is 117 ft (35.7 m) long with a longest span of 53 ft (16.2 m) and a deck 36 ft wide.
Who owns NE Marymoor Way over Sammamish Slough?
It is owned by the Local Park, Forest, or Reservation Agency.