U.S. Highway 101 over Irwin Creek
GoodMarin County, California · 04-MRN-101-11.20-SRF · Structure no. 27 0097
- Built
- 1895
- 130 years old, rebuilt 1987
- Condition
- Good
- inspected April 2023
- Type
- Culvert
- Concrete
- Length
- 207 ft
- 1 main span
- Daily traffic
- 129,000
- 2009 count
- Owner
- State
- State Highway Agency
About this bridge
U.S. Highway 101 over Irwin Creek is a concrete culvert carrying U.S. Highway 101 over Irwin Creek in Marin County, California. It was built in 1895 and reconstructed in 1987, so it is 130 years old, older than the California average of 54.8 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 129,000 vehicles a day, projected to reach 183,573 by 2045. The structure is 207 ft (63 m) long. If it were closed, the detour would be 1.2 mi (2 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 |
|---|---|---|
| Channel and channel protection | 7 Good | Some minor problems. |
| Culvert | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was U.S. Highway 101 over Irwin Creek built?
It was built in 1895, making it 130 years old in 2025. It was reconstructed in 1987.
What condition is U.S. Highway 101 over Irwin Creek 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 April 2023.
How much traffic does U.S. Highway 101 over Irwin Creek carry?
About 129,000 vehicles per day (2009 count).
How long is U.S. Highway 101 over Irwin Creek?
The structure is 207 ft (63 m) long with a longest span of 15 ft (4.6 m).
Who owns U.S. Highway 101 over Irwin Creek?
It is owned by the State Highway Agency.