Mendocino County, CA Sign Regulations: Political Signs (2026)

Sign regulation in unincorporated Mendocino County is split by zone: inland signs are governed by Zoning Code Chapter 20.184 (Sign Regulations) and coastal signs by the Coastal Zoning Code. Under Chapter 20.184, a temporary sign generally may not exceed a total of 32 square feet in area and is intended to be displayed for less than 90 days, with an Administrative Permit referenced for temporary signage. The County's exempt-sign list (Section 20.184.035) covers items such as legally required directional or warning signs, official notices, house numbers, flags and works of art, but does not specifically enumerate political or campaign signs. Importantly, political and other non-commercial signs are constitutionally protected speech, and California law (including Outdoor Advertising Act provisions and case law) limits how strictly local governments may restrict temporary political signs on private property; agencies typically cannot single out political signs for harsher treatment than other temporary signs. Signs placed within the right-of-way of a state highway must comply with Caltrans Outdoor Advertising rules, which require placement on private property with the owner's consent, prohibit signs in the highway right-of-way, and require removal within a set period after the election. Because the County does not publish a separate political-sign section, residents should follow the temporary-sign size and time standards and, in the Coastal Zone, confirm whether a Coastal Development Permit applies. Verify current rules with Planning & Building Services.