Jefferson County, MO Animal Ordinances: Dog Leash Laws (2026)

240, Running At Large Prohibited, states that no person shall permit an animal to run at large in the unincorporated area of Jefferson County, and authorizes the Animal Control Manager or agents to take up and hold any animal found running or being at large contrary to the chapter. Officers may pursue an at-large animal across, or onto, unenclosed private property unless the property owner specifically prohibits it. 040 defines AT LARGE as a condition where an animal is off the property of its owner, harborer, keeper, or other consenting property owner and not under the physical restraint of a responsible person capable of controlling it; a dog actively engaged with its owner present, in hunting, training, herding, or showing, is not considered at large.

The code does not require a specific leash length or material, but a dog off its owner's property without a person physically able to control it, whether by leash, hand, or other restraint, meets the at-large definition and can be impounded. 210 regardless of whether the running-at-large violation is separately charged.