State requirement for all dogs to be on leashes in public is a type of statutory law.
In legal terms, a statutory law means that the law was passed by a local or state legislature.
In this case of dog regulations, you have to check with your local Congress because laws vary from state to state. Furthermore, some states have regulations, but local governments could have another or extra regulation. For instance, the states of Pennsylvania and Michigan prohibit the dog to be unleashed in public areas.
