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St. Charles County, MO Sign Regulations: Digital Billboards (2026)

Significant Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Minimum image duration
10 seconds, static only
Daytime brightness cap
5,000 nits maximum
Nighttime brightness cap
500 nits, auto-dimmed
Allowed locations
Named interstates/US/state routes only
Audio
Speakers prohibited on billboards

Summary

Electronic off-premise billboards are legal only on designated highways and must hold static images for at least 10 seconds with no motion or flashing.

These county ordinances apply to unincorporated areas of St. Charles County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

Electronic display techniques are permitted as off-premise signs when meeting criteria found herein... The full off-premise sign image or any portion thereof must have a minimum duration of ten (10) seconds and must be a static display. No portion of the image may flash, scroll, twirl, change color or in any matter imitate movement... The sign must not exceed a maximum illumination of 5,000 nits (candelas per square meter) during daylight hours and a maximum illumination of 500 nits (candelas per square meter) between dusk and dawn.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4863880; v61 updated 2026-05-11; through 05-11-2026).

Full Breakdown

St. Charles County permits LED and electronic-display off-premise signs, but confines them to specific corridors, I-64, I-70, US 40, US 61, Route 94, Route 364, and Route 370, plus smaller 64-square-foot electronic signs on lettered state routes. Any electronic billboard must hold each image at least 10 seconds, change only by instant re-pixelation, cap brightness at 5,000 nits by day and 500 nits at night with automatic dimming, and cannot use video, flashing, or audio.

Violations & Fines

Violating operational standards (motion, flashing, excess brightness, audio) or erecting an electronic off-premise sign outside the approved highway corridors is a zoning code violation enforced by the Division of Planning and Zoning, subject to permit denial or revocation.

Frequently Asked Questions

Can I put an electronic billboard anywhere in St. Charles County?
No. Off-premise electronic signs are allowed only along specific designated highways like I-64, I-70, US 40, US 61, and a handful of named state routes.
Can a digital billboard show video or scrolling text?
No. Each image must be static for at least 10 seconds, changing only by instant re-pixelation: no video, flashing, scrolling, or imitation of movement is allowed.

Sources & Official References

Other rules in St. Charles County

Fence Regulations: Height LimitsSome RestrictionsPolitical SignsSome RestrictionsHoliday DisplaysFew RestrictionsGarage Sale SignsSome RestrictionsWindow SignsSome RestrictionsFence Regulations: Retaining WallsSome RestrictionsFence Regulations: Material RestrictionsSome RestrictionsAnimal Ordinances: Veterinary Clinic ZoningSome RestrictionsAnimal Ordinances: Pet Store RulesSome RestrictionsAnimal Ordinances: Mandatory Spay/NeuterSome Restrictions

All St. Charles County rules

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