Charleston, SC Sign Regulations: Freeway-Facing Signs (2026)

Section 54-415(n) is Charleston's only avenue for a new off-premises sign, commonly a billboard, and it is narrow by design. The sign must be located entirely within the HI (Heavy Industrial) zoning district, and the entire sign and its supporting structure must sit within 100 feet of an interstate highway; outside that combination of district and proximity, off-premises advertising signs are barred citywide under Section 54-404(c), which prohibits off-premises signs generally except billboards permitted under Section 54-415(n) or already standing as non-conforming signs under Section 54-420.

Where a new billboard is allowed, only one per lot may be built, and it must clear four numeric hurdles: a minimum 1,000-foot separation from the next off-premises sign along the same street or thoroughfare, a minimum 500-foot separation from any residentially zoned property, a minimum five-foot setback from the property lines, and a location on high ground only, no billboards in marsh or floodway areas. Height and size are capped together: the sign cannot exceed 25 feet above the roadbed it faces or 35 feet above the ground, whichever is less, and its advertising surface cannot exceed 150 square feet on one side.

Older billboards along Interstate System Roads that predate February 1, 2017, and do not meet these standards can stay in place and even be repaired or relocated under Section 54-420(f), but only within 500 feet of their original location, along the same interstate, and without increasing sign face size or adding illumination if they were unlit on the effective date.