Arun is a local government district in West Sussex, England. Its council is based in Littlehampton. The district's other towns are Arundel and Bognor Regis. The district is named after the River Arun, which runs through the centre of the district. Parts of the district fall within the South Downs National Park.

West Sussex is a ceremonial county in South East England. It is bordered by Surrey to the north, East Sussex to the east, the English Channel to the south, and Hampshire to the west. The largest settlement is Crawley, and the county town is the city of Chichester.