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S-26-646 over Mitchell Swamp

Horry County, South Carolina · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

S-26-646 over Mitchell Swamp in Horry County, South Carolina, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
It was built in 1966 and reconstructed in 1993, making it 59 years old at the 2025 inventory.
It carries about 250 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 231 of the 480 inventoried bridges in Horry County rated fair (48.1%); 24 (5.0%) are rated poor.
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.

Component ratings

Source: FHWA National Bridge Inventory, 2025 data as reported by the South Carolina department of transportation.

Bridge	Built	Vehicles/day	Condition
US 501 over Intercoastal Waterway	1963	63,800	Fair
US 501 Byp over U.S.701	1958	56,800	Poor
US 501 Byp over Waccamaw River	1958	56,800	Poor
S-26-1315 over Grissom Parkway Tunnel	2002	55,000	Good
S-26-1315 over Sc 31	2002	55,000	Good
S-26-1315 over L-6311	2002	55,000	Good