Transport in South Australia is provided by a mix of road, rail, sea and air transport. The capital city of Adelaide is the centre to transport in the state. With its population of 1.4 million people, it has the majority of the state's 1.7 million inhabitants. Adelaide has the state's major airport and sea port.
Road transport is predominant in the state. Its extensive road network connect the state's regional centres and other towns, few of which have populations greater than 10,000. Private cars are a dominant form of transport throughout.
Adelaide is an isolated city with Melbourne, the nearest city, being 800 km away. This makes air transport an important form of travel to other cities.
The state is a land transport hub between the eastern states of Australia, Western Australia and the Northern Territory. The town of Port Augusta at the top of the Spencer Gulf is the only railway link, and one of only two sealed road links from the eastern states. Most major surface freight passes through this town.