US 278 WB over Mackay Creek
Beaufort County, South Carolina · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 278 WB over Mackay Creek in Beaufort County, South Carolina, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1983, making it 42 years old at the 2025 inventory.
- It carries about 28,950 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 40 of the 72 inventoried bridges in Beaufort County rated fair (55.6%); 4 (5.6%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 2024, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (32.23068, -80.79177)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 2,230 ft |
| Location | Hilton Head Island |
| NBI structure number | 000000000007650 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Carolina department of transportation.
Busiest bridges in Beaufort County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 278 EB over Okatie River | 1991 | 33,950 | Fair |
| US 278 EB over Sc 170 | 1991 | 33,950 | Good |
| US 278 WB over Okatie River | 1991 | 33,950 | Fair |
| US 278 WB over Sc 170 | 1991 | 33,950 | Good |
| US 21/RIBAUT Rd over Battery Creek Overflow | 1993 | 32,900 | Fair |
| US 21 over Battery Creek | 1994 | 32,900 | Fair |
All bridges nearby: Beaufort County, SC bridge conditions · every bridge in Beaufort County · South Carolina bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.