Stc 7787;PLYMOUTH over Boise River & Canal
PoorCanyon County, Idaho · Caldwell Ncl · Structure no. 000000000026725
- Built
- 1922
- 103 years old
- Condition
- Poor
- inspected July 2024
- Type
- Truss - Thru
- Steel
- Length
- 388 ft
- 3 main spans
- Daily traffic
- 2,100
- 2023 count
- Owner
- Local
- Other Local Agency
About this bridge
Stc 7787;PLYMOUTH over Boise River & Canal is a steel truss - thru carrying Stc 7787;PLYMOUTH over Boise River & Canal in Canyon County, Idaho. It was built in 1922, so it is 103 years old, older than the Idaho average of 45.3 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
It carries about 2,100 vehicles a day, roughly 6% of them trucks, projected to reach 3,150 by 2042. The structure is 388 ft (118.3 m) long and 23 ft wide. If it were closed, the detour would be 1.9 mi (3 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Superstructure | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| Substructure | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| 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 Stc 7787;PLYMOUTH over Boise River & Canal built?
It was built in 1922, making it 103 years old in 2025.
What condition is Stc 7787;PLYMOUTH over Boise River & Canal in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in July 2024.
How much traffic does Stc 7787;PLYMOUTH over Boise River & Canal carry?
About 2,100 vehicles per day (2023 count), of which roughly 6% are trucks.
How long is Stc 7787;PLYMOUTH over Boise River & Canal?
The structure is 388 ft (118.3 m) long with a longest span of 128 ft (39 m) and a deck 23 ft wide.
Who owns Stc 7787;PLYMOUTH over Boise River & Canal?
It is owned by the Other Local Agency.