SR 9 over Black Slough
GoodWhatcom County, Washington · 9.7 N Skagit CO · Structure no. 0004281D0000000
- Built
- 1952
- 73 years old, rebuilt 1978
- Condition
- Good
- inspected May 2023
- Type
- Slab
- Wood or Timber
- Length
- 36 ft
- 2 main spans
- Daily traffic
- 3,517
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
SR 9 over Black Slough is a wood or timber slab carrying SR 9 over Black Slough in Whatcom County, Washington. It was built in 1952 and reconstructed in 1978, so it is 73 years old, older than the Washington average of 49.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 3,517 vehicles a day, roughly 15% of them trucks, projected to reach 4,774 by 2039. The structure is 36 ft (11 m) long and 30 ft wide. If it were closed, the detour would be 3.7 mi (6 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was SR 9 over Black Slough built?
It was built in 1952, making it 73 years old in 2025. It was reconstructed in 1978.
What condition is SR 9 over Black Slough in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in May 2023.
How much traffic does SR 9 over Black Slough carry?
About 3,517 vehicles per day (2023 count), of which roughly 15% are trucks.
How long is SR 9 over Black Slough?
The structure is 36 ft (11 m) long with a longest span of 17 ft (5.2 m) and a deck 30 ft wide.
Who owns SR 9 over Black Slough?
It is owned by the State Highway Agency.