U.S. Route 378 (US 378) is a spur of US 78 in the U.S. states of Georgia and South Carolina. The U.S. Highway runs from US 78, Georgia State Route 10 (SR 10), SR 17, and SR 47 in Washington, Georgia, east to US 501 Business in Conway, South Carolina. US 378 connects the Central Savannah River Area in both states with the Midlands and Pee Dee regions of South Carolina. The U.S. Highway's western portion, which connects Washington and Lincolnton in Georgia and McCormick, Saluda, and Lexington in South Carolina, is mainly a rural highway. US 378 is a major suburban and urban highway through Lexington and South Carolina's state capital, Columbia. The highway has a lengthy concurrency with US 76 between Columbia and Sumter and serves as a major route between the Midlands and the Myrtle Beach area, between which the highway has a business route through Lake City. Route description US 378 has a length of in Georgia and spans in South Carolina. The U.S. Highway is a part of the National Highway System from US 178 in Saluda east to US 501 and US 701 in Conway. Georgia US 378 begins at an intersection on the eastern edge of the city of Washington with US 78, SR 10, and SR 17, which form the north–south axis of the junction, and US 78 Business, SR 47, SR 10 Business, and SR 17 Business, which heads west on Robert Toombs Avenue toward downtown Washington. US 378 and SR 47 head east on Lincolnton Road, also known as Joe Wheeler Highway, which starts as a four-lane divided highway but becomes two lanes a short distance east of the intersection. Shortly after the Wilkes–Lincoln county line, the highways, now part of Washington Highway, meet the western end of SR 220, a C-shaped route through southern Lincoln County. US 378 and SR 47 gradually curve north and enter the city of Lincolnton as Washington Street. SR 47 splits east from the U.S. Highway and SR 43 begins to run concurrently with US 378 at their intersection with Elm Street. The highways pass along the west side of downtown Lincolnton and curve northeast, meeting the southern end of SR 79 (Goshen Street) before leaving the city. US 378 and SR 43 continue northeast on McCormick Highway, which meets the northern end of SR 43 Connector (Old Petersburg Road) a short distance east