SR 300 over Union River
FairMason County, Washington · 2.9 E State Park · Structure no. 0006393A0000000
- Built
- 1960
- 65 years old
- Condition
- Fair
- inspected March 2024
- Type
- Stringer/Multi-beam or Girder
- Wood or Timber
- Length
- 65 ft
- 3 main spans
- Daily traffic
- 12,136
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
SR 300 over Union River is a wood or timber stringer/multi-beam or girder carrying SR 300 over Union River in Mason County, Washington. It was built in 1960, so it is 65 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 12,136 vehicles a day, roughly 4% of them trucks, projected to reach 16,046 by 2039. The structure is 65 ft (19.8 m) long and 28 ft wide. If it were closed, the detour would be 9.9 mi (16 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 | 7 Good | Some minor problems. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was SR 300 over Union River built?
It was built in 1960, making it 65 years old in 2025.
What condition is SR 300 over Union 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 March 2024.
How much traffic does SR 300 over Union River carry?
About 12,136 vehicles per day (2023 count), of which roughly 4% are trucks.
How long is SR 300 over Union River?
The structure is 65 ft (19.8 m) long with a longest span of 21 ft (6.4 m) and a deck 28 ft wide.
Who owns SR 300 over Union River?
It is owned by the State Highway Agency.