US 501 Nbl over Back Swamp
FairMarion County, South Carolina · 3 MI W of Horry CO · Structure no. 000000000000560
- Built
- 1931
- 94 years old, rebuilt 1976
- Condition
- Fair
- inspected July 2024
- Type
- Tee Beam
- Concrete
- Length
- 225 ft
- 9 main spans
- Daily traffic
- 9,700
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 501 Nbl over Back Swamp is a concrete tee beam carrying US 501 Nbl over Back Swamp in Marion County, South Carolina. It was built in 1931 and reconstructed in 1976, so it is 94 years old, older than the South Carolina average of 48 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 9,700 vehicles a day, roughly 17% of them trucks, projected to reach 16,878 by 2043. The structure is 225 ft (68.6 m) long and 43 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US 501 Nbl over Back Swamp built?
It was built in 1931, making it 94 years old in 2025. It was reconstructed in 1976.
What condition is US 501 Nbl over Back Swamp 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 July 2024.
How much traffic does US 501 Nbl over Back Swamp carry?
About 9,700 vehicles per day (2023 count), of which roughly 17% are trucks.
How long is US 501 Nbl over Back Swamp?
The structure is 225 ft (68.6 m) long with a longest span of 25 ft (7.6 m) and a deck 43 ft wide.
Who owns US 501 Nbl over Back Swamp?
It is owned by the State Highway Agency.