The county was named after the River Avon, which runs through the area. It was formed from parts of the historic counties of Gloucestershire and Somerset, together with the City of Bristol. In 1996, the county was abolished and the area split between the new unitary local authorities of Bath and North East Somerset, North Somerset, South Gloucestershire and the City of Bristol which became a ceremonial county in its own right.
The Avon name is still used for some purposes. The area had a population of approximately 1.08 million people in 2009.
Avon was divided into six "units" or districts (see Wikipedia for a map):