St. Clair County, IL Sign Regulations: Freeway-Facing Signs (2026)

St. Clair County's Zoning Code, Article VII, Section 40-7-4(A)(2), sets the location standards for an 'Advertising Sign/Billboard,' defined as a sign directing attention to a business or service offered elsewhere than on the lot where the sign stands. Every advertising sign must comply with the Highway Advertising Control Act of 1971. 5 miles from the nearest corporate limits of any municipality; they cannot stand nearer than 200 feet to a building or structure; on the same side of a highway, billboards must be spaced at least 500 feet apart; and none may go up along a roadway within 500 feet of an interchange, rest area, or weigh station, measured along the main-traveled way from the start or end of pavement widening at that exit or entrance.

Section 40-7-4(A)(2)(f) then narrows where a billboard can legally go at all: advertising signs and billboards are not permitted along County or Township highways, roads, or local streets, which as a practical matter routes them to state and federal highway frontage instead. Height is separately capped at 35 feet from ground level, rising to 45 feet in the 'B-2,' 'I-1,' and 'I-2' zoning districts, and total sign area tops out at 300 square feet or one square foot per linear foot of lot frontage, whichever is less. A permit under Section 40-7-2(C) is required before construction, and the County Zoning Administrator reviews the application against these standards.