US 101 over Mud Bay
FairThurston County, Washington · 1.3 S JCT SR 8 · Structure no. 0005677A0000000
- Built
- 1958
- 67 years old
- Condition
- Fair
- inspected April 2024
- Type
- Slab
- Concrete Continuous
- Length
- 290 ft
- 8 main spans
- Daily traffic
- 21,984
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 101 over Mud Bay is a concrete continuous slab carrying US 101 over Mud Bay in Thurston County, Washington. It was built in 1958, so it is 67 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 21,984 vehicles a day, roughly 6% of them trucks, projected to reach 32,310 by 2039. The structure is 290 ft (88.4 m) long and 34 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 | 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 Mud Bay built?
It was built in 1958, making it 67 years old in 2025.
What condition is US 101 over Mud Bay 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 2024.
How much traffic does US 101 over Mud Bay carry?
About 21,984 vehicles per day (2023 count), of which roughly 6% are trucks.
How long is US 101 over Mud Bay?
The structure is 290 ft (88.4 m) long with a longest span of 40 ft (12.2 m) and a deck 34 ft wide.
Who owns US 101 over Mud Bay?
It is owned by the State Highway Agency.