Does my state have a leash law?
This simple question does not have a simple answer. Instead, like many areas of the law, it depends. Even though a state might not require that an owner use a leash when the dog is off-premises, the law may allow impoundment of "at-large" dogs. A dog that is at large may be defined as one who is off the owner's property unaccompanied or not on a leash. Further, a state may only require a leash in certain areas like parks and wildlife areas, or during the period between sunset and sunrise.
Additionally, while your state may not have a general requirement, your local government may. Many states view animal control (leash laws, number of animals one can maintain, prohibition on types of animals one can keep) as matters of local concern. Before you conclude that there is no leash requirement in your area, call your city or county code office to check your local law.