Riverside County, CA Sign Regulations: Freeway-Facing Signs (2026)

Section 17.252.030 opens by banning any outdoor advertising display in the unincorporated county unless it follows the section's permit and design standards. Zoning comes first: displays are permitted only in the C-1/C-P, M-SC, M-M and M-H zones and are 'expressly prohibited in all other zones.' Height is measured two ways, twenty-five feet from the roadbed of the adjacent freeway or highway the display faces, or twenty-five feet from the grade it's built on, whichever number is greater, so a billboard on a raised pad can't use the extra grade height to sit taller over the freeway itself. The 660-foot rule applies specifically to primary highways: no display within 660 feet of a primary highway right-of-way, with copy visible from it, can go up without a valid State Outdoor Advertising Permit first.

Beyond height and the highway buffer, a single billboard face can't exceed 300 square feet, displays must sit at least 500 feet from any other billboard on the same side of the highway, and at least 150 feet from a residentially zoned parcel with a house or approved building permit on it. An owner boxed in by a later-built freeway noise wall can apply for a height adjustment up to 40 feet, but only with a line-of-sight study proving the wall blocks the display from approaching traffic. The planning director has 45 days to approve or deny a complete permit application, and a denial can be appealed to superior court by writ of administrative mandamus.