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. The highway curves to the east-northeast and crosses over Deadfall Swamp, Roberts Swamp, and Twomile Swamp before entering . While there, it curves to a more easterly direction. 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.[2]