Rural delivery service refers to services for the delivery of mail to rural areas. Examples include Rural Free Delivery in the United States and the Rural Mail Box addressing system in Australia. Such services may be based on post roads, or may make use of alternate forms of transport, such as mail delivery by animal, including dogs and pigeons.
Such services are in contrast to those suitable only to urban areas, such as the Prague pneumatic post and the London Pneumatic Despatch Company.
References
Rural delivery service Wikipedia(Text) CC BY-SA