US 101 over Hamma Hamma River
GoodMason County, Washington · 5.3 S Jefferson CO · Structure no. 0000734B0000000
- Built
- 1924
- 101 years old
- Condition
- Good
- inspected June 2024
- Type
- Arch - Thru
- Concrete
- Length
- 154 ft
- 1 main span
- Daily traffic
- 2,911
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 101 over Hamma Hamma River is a concrete arch - thru carrying US 101 over Hamma Hamma River in Mason County, Washington. It was built in 1924, so it is 101 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 2,911 vehicles a day, roughly 20% of them trucks, projected to reach 3,502 by 2039. The structure is 154 ft (46.9 m) long and 26 ft wide. If it were closed, the detour would be 37.9 mi (61 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 US 101 over Hamma Hamma River built?
It was built in 1924, making it 101 years old in 2025.
What condition is US 101 over Hamma Hamma River 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 June 2024.
How much traffic does US 101 over Hamma Hamma River carry?
About 2,911 vehicles per day (2023 count), of which roughly 20% are trucks.
How long is US 101 over Hamma Hamma River?
The structure is 154 ft (46.9 m) long with a longest span of 150 ft (45.7 m) and a deck 26 ft wide.
Who owns US 101 over Hamma Hamma River?
It is owned by the State Highway Agency.