South Carolina Highway 742 (SC 742) is a primary state highway in the U.S. state of South Carolina. It connects Chesterfield with Wadesboro, North Carolina.

SC 742 is a two-lane rural highway that traverses 3.4 miles (5.5 km), from SC 145, near Chesterfield, to the North Carolina state line.

Established in 1942 as a renumbering of SC 850 and to match NC 742, little has changed since.

Established in 1940 as a new primary routing from SC 85 to the North Carolina state line. It was renumbered to SC 742 in 1942.

The entire route is in Chesterfield County.