South Carolina Highway 400 (SC 400) is a 12.440-mile-long (20.020 km) state highway in the U.S. state of South Carolina.

The highway connects Norway with rural areas of Orangeburg County.

SC 400 begins at an intersection with U.S. Route 321 (US 321) and SC 332 (Savannah Highway/Norway Road) in Norway, Orangeburg County.

It travels to the east-southeast and leaves the town limits.

SC 400 heads to the east-northeast again before it meets its eastern terminus, an intersection with SC 4 (Neeses Highway) at a point west of Edisto.