Sign Regulations in Jefferson County, MO (2026)
5 rules for unincorporated Jefferson County, Missouri.
Verified from official government sources
Political Signs
Jefferson County allows political signs without a permit if they stay at or under thirty-two square feet, or ninety-six square feet along State lettered or numbered routes, and are posted no more than ninety days before an election and removed within fifteen days after it.
Jefferson County Political Sign Size and Timing Rule
Light RestrictionsJefferson County, MO Unified Development Ordinance § 400.4250(A)(6) (Signs Not Requiring A Permit)
Political signs, provided that the signs do not exceed thirty-two (32) square feet in area (except along State lettered or numbered roads where political signs shall not exceed ninety-six (96) square feet in area), are not erected more than ninety (90) days prior to the election and are removed no later than fifteen (15) days after the election.
Garage Sale Signs
Jefferson County lets residents post yard and garage sale signs without a permit, but caps them at twelve square feet and limits their display window: no earlier than sunrise on the sale's first day, and gone by sunset on its second day.
Jefferson County Yard and Garage Sale Sign Rule
Light RestrictionsJefferson County, MO Unified Development Ordinance § 400.4250(A)(4) (Signs Not Requiring A Permit)
Yard and garage sale signs that do not exceed twelve (12) square feet in area. Such signs shall not be erected prior to sunrise of the first (1st) day of the event and shall be removed no later than sunset of the second (2nd) day of the event.
Digital Billboards
Jefferson County bars flashing, blinking or animated signage countywide but carves out programmable electronic message boards. On-premise boards may run a steady message with limited scroll or fade effects; off-premise static signs may only show electronic time, temperature or pricing displays.
Jefferson County Electronic Message Board Sign Rule
Significant RestrictionsJefferson County, MO Unified Development Ordinance § 400.4270(A)(2) (General Standards For Signs)
No sign shall contain flashing lights (except State or County road projects), intermittent lights, animators or mechanical movements of any kind, except clocks. On-premise programmable electronic message boards are permitted, but may display a steady message type only. Within the steady message the following modes of operation are permitted: down scroll; up scroll; melt; grow; write-on; and rev...
Window Signs
Jefferson County caps window signage under its zoning code: permanent signs may cover no more than 15% of a building facade's window area, and businesses may add temporary signs on an additional 15% of the facade for up to 14 days in any 12-month period. The rule applies countywide to premises and shopping-center occupants alike.
Jefferson County Window Sign Coverage Limits
Some RestrictionsJefferson County, MO Code of Ordinances § 400.4370(B)
Window Signs. A premises, or an occupant of a shopping center or multi-use building, may display permanent window signs not to exceed fifteen percent (15%) of the window area of the facade of the building; and temporary signs, not to exceed an additional fifteen percent (15%) of the facade of the building, for no more than fourteen (14) days during any twelve (12) consecutive calendar months.
Freeway-Facing Signs
Jefferson County confines new billboards to parcels touching a short list of major routes: Interstate 55, U.S. Highways 61 and 67, and State Highways 30, 141 and 231. A billboard proposed anywhere else in the unincorporated county does not qualify under Section 400.4310.
Jefferson County Billboard Highway Frontage Rule
Significant RestrictionsJefferson County, MO Unified Development Ordinance § 400.4310(A)(3) (Billboards)
Billboards may be located only on parcels contiguous to the rights-of-way of Interstate 55, U.S. Highways 61 and 67 and State Highways 30, 141 and 231 in unincorporated Jefferson County.
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