O'Fallon, MO Sign Regulations: Freeway-Facing Signs (2026)

170(B)(1) layers on more geographic limits. No billboard may go up within one mile of another existing billboard on the same side of the same highway, measured along the nearest edge of pavement, regardless of whether that other sign sits inside or outside O'Fallon's city limits. A billboard also cannot sit within 500 feet of an intersection on a dual highway, must be set back at least 30 feet from the road right-of-way even though billboards are otherwise exempt from normal zoning setbacks, and cannot be located within a fifty-foot radius of any building or within 1,000 feet of the nearest point of any structure on residentially zoned property.

Size and height are capped too: a maximum of 672 square feet per face, twenty feet in height and fifty feet in length, with an overall structure height ceiling of 45 feet above ground or adjoining street grade. A non-conforming billboard can only be relocated through a replacement-and-relocation agreement approved by the City Council after Planning and Zoning Commission review of traffic, parking and compatibility impacts.