US 21 over I-77
FairYork County, South Carolina · 2.6 MI S of Rock Hill · Structure no. 000000000006816
- Built
- 1975
- 50 years old
- Condition
- Fair
- inspected March 2024
- Type
- Frame
- Steel
- Length
- 270 ft
- 4 main spans
- Daily traffic
- 25,600
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 21 over I-77 is a steel frame carrying US 21 over I-77 in York County, South Carolina. It was built in 1975, so it is 50 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 5 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 25,600 vehicles a day, roughly 8% of them trucks, projected to reach 33,536 by 2043. The structure is 270 ft (82.3 m) long and 88 ft wide.
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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US 21 over I-77 built?
It was built in 1975, making it 50 years old in 2025.
What condition is US 21 over I-77 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 US 21 over I-77 carry?
About 25,600 vehicles per day (2023 count), of which roughly 8% are trucks.
How long is US 21 over I-77?
The structure is 270 ft (82.3 m) long with a longest span of 90 ft (27.4 m) and a deck 88 ft wide.
Who owns US 21 over I-77?
It is owned by the State Highway Agency.