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St. Charles County, MO Animal Ordinances: Microchipping (2026)

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

Key Facts

Microchip required
bite quarantine, at-large impound, exotic pet >30 days
Microchip fee
$10.00 (§205.240)
Contact update window
30 days after any change
Penalty
up to $1,000 fine or 1 year jail
Enforcement
Division of Humane Services / County Counselor

Summary

St. Charles County requires a microchip whenever the Division of Humane Services impounds a dog or cat for running at large, holds an animal after a bite investigation, or licenses a wild or exotic animal kept in the county more than thirty days. Owners who skip the chip, or let its registered contact information go stale, commit a misdemeanor under Section 205.050.

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.

Any animal which is apprehended running at large or who has bitten a human being or animal shall be photographed and microchipped by the Division Director as soon as is reasonably practicable after a bite or running at large incident or if the animal is impounded prior to its release. ... An owner or competent person is guilty of failure to register/vaccinate or microchip when he: ... Fails to implant a microchip in an animal when required by Sections 205.080, 205.140 and/or 205.141; or Fails to maintain current contact information with the microchip registry company or the Division by which the owner or competent person of the microchipped animal can be reached, when the microchip is required by Sections 205.080, 205.140 and/or 205.141. Said contact information shall be updated within thirty (30) days of any change.

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

240 back to the owner. 141(C) gives the previous owner ten days to tell the Division Director, in writing, the new owner's name, address and phone number. 141, or if they fail to keep the microchip registry company or the Division updated with current contact information, which must be corrected within thirty days of any change. 141 microchip. 260.

Violations & Fines

A Section 205.050 violation is a misdemeanor under Section 205.250: a fine of up to $1,000.00, up to one year in the St. Charles County Jail, or both, with a separate offense charged for each day the failure continues. An at-large animal without proof of its Section 205.141 microchip and rabies shot also cannot be released from the county shelter until vaccinated.

Frequently Asked Questions

Does every pet in the county need a microchip?
No. Routine ownership only calls for registration and rabies vaccination. A microchip is mandated only when the Division impounds your pet after it runs at large, holds it for a bite quarantine under Section 205.140, or when you keep a wild or exotic/dangerous animal in the county for more than thirty days under Section 205.080.
What if I move and don't update the chip registry?
Section 205.050(A)(5) makes that a separate violation. Once a microchip is required under Sections 205.080, 205.140 or 205.141, you must keep the microchip registry company or the Division current on how to reach you, and report any change within thirty days.
Who pays for the microchip?
The owner does. Section 205.240 sets the Division's microchip fee at $10.00, and that charge, along with any impound and boarding fees, is billed to the owner before the Division releases an animal it has chipped under Section 205.141.
Can a lost dog be picked up without being chipped first?
Yes, but it can't come home without one. Section 205.235 blocks release of any animal apprehended at large until the owner shows proof of both rabies vaccination and the microchip Section 205.141 requires; missing either means the Division vaccinates and chips before release.

Sources & Official References

Other rules in St. Charles County

Dog Leash LawsSome RestrictionsChickens & LivestockSignificant RestrictionsFence Regulations: Height LimitsSome RestrictionsCat RulesSome RestrictionsPet Groomer RulesSome RestrictionsMandatory Spay/NeuterSome RestrictionsWildlife FeedingHeavy RestrictionsVeterinary Clinic ZoningSome RestrictionsBreed RestrictionsSignificant RestrictionsPet Store RulesSome RestrictionsPet LimitsSome RestrictionsBeekeepingSignificant RestrictionsExotic PetsHeavy RestrictionsFence Regulations: Retaining WallsSome RestrictionsFence Regulations: Material RestrictionsSome RestrictionsFire Regulations: Propane StorageSome RestrictionsFire Regulations: FireworksSignificant RestrictionsEnvironmental Rules: Stormwater ManagementSome Restrictions

All St. Charles County rules

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