South Carolina Highway 34 is a 188.6-mile (303.5 km) state highway that extends from Dillon in Dillon County to Greenwood in Greenwood County. The route runs generally east-to-west across most of the northern portion of the state, and is one of South Carolina's longest state highways.

Starting at a junction with U.S. Highways 301 and 501 in Dillon, SC 34 proceeds generally southwest through an intersection with Interstate 95 and over the Great Pee Dee River and nearby marshland to Darlington. The road then runs in a generally westerly direction past Lee State Natural Area through Bishopville and Camden and roughly parallel to Interstate 20. SC 34 then proceeds to an intersection with Interstate 77 and through Winnsboro and Sumter National Forest to an intersection with Interstate 26. The road then passes through Newberry, over the Saluda River, and through Ninety Six on its way to the final junction with U.S. Highways 25 and 178 Business in Greenwood.

An original part of the South Carolina state route system, in 1922 the road ran from Darlington to Ridgeway. In 1933 the road was extended to Dillon and about 1943 a bridge over the Pee Dee river was opened. In the early 1950s the road was extended to Greenwood, creating the current configuration. SC 34 was bypassed south around Newberry in 1976 and the original route through the town remained as SC 34 Business. The first part of the road to be paved was the section though Camden in 1929. Over the next several years other parts were paved until the road was fully paved by the early 1940s. During the past several decades, much of the route has been widened to four lanes.

South Carolina Highway 34 Business begins on SC 34 and US 76 just a mile and half away from downtown Newberry. It lasts for about 3 miles (3 km). Nearly a half-mile into SC 34 Business serves as the northern terminus of US 76. This is shortly followed by US 76. After going another three-quarters of a mile, SC 34 BUS ends at SC 34 northeast of Newberry.