US 78 enters South Carolina by crossing the Savannah River in North Augusta; sharing concurrences with US 1, US 25, US 278 and SC 121. In the immediate area, it sheds most concurrences, sharing only with US 1 towards Aiken; it also connects with I-520, which is a partial beltway around the Augusta metropolitan area. In Aiken, it travels through the downtown area, where US 1 splits north towards Columbia. West of Williston is SC 781, which connects back with US 278; the routing allows travelers to bypass Aiken all together between Williston and Augusta. Traveling in a southeasterly direction, it goes through the cities and towns of Williston, Blackville, Denmark, Bamberg, Branchville and St. George, where connects with I-95. Continuing east, it passes through Dorchester and begins to parallel with I-26 in a southeasterly direction through Summerville. It crosses into Charleston County at Lincolnville, where the highway skirts just inches south of the Berkeley County line. In North Charleston, US 78 shares a concurrency with US 52, as it connects with I-526. Entering Charleston, it splits with US 52 and goes south along King Street; its eastern terminus at Line Street, a block away from US 52's eastern/southern terminus and nearby to I-26/US 17 interchange. US 78 is a predominantly two-lane rural highway connecting much of the Lowcountry. Wider sections are found between North Augusta-Aiken, St. George and North Charleston. Though it provides the most direct route between Augusta and Charleston, it is not a busy route because of the many cities and towns it goes through.
History
Established in 1927 as an original US highway, it traveled closely as it does today; from North Augusta to Charleston, connecting the cities and towns of Aiken, Bamberg, St. George, and North Charleston. By 1931, US 78 was rerouted north of Summerville and Lincolnville, leaving Richardson Avenue/Lincoln Avenue. Around 1939, US 78 was realigned from Meeting Street to Rivers Street, south of Durant Avenue in the Charleston area. Also in 1939, US 78 was fully paved in the state, its last unpaved section was between St. George and US 178. By 1952, US 78 was placed on new four-lane highway bypassing Clearwater, Burnettown, and Gloverville; also by same year a new bridge was constructed over the Savannah River, leaving Fifth Street Bridge. By 1967, US 78 was adjusted to bypass south of mainstreet Blackville, leaving a secondary road, but was later upgraded as a connector.
