Each capital city hosts the judicial, administrative and legislative functions for their jurisdiction. In the case of the states and internal territories, their capital cities also happen to be the most populous city in their respective jurisdiction.
The Australian external territory of Norfolk Island has its official capital at Kingston, although this acts merely as the administrative centre of government; its de facto capital is Burnt Pine.
* While Canberra is the capital of Australia, it is not the capital of the ACT in any official sense; it is the principal settlement within the territory and can be considered as broadly having the same geographical boundaries as the ACT.
** in 1911, South Australia transferred responsibility for governing the Northern Territory to the Commonwealth Government of Australia. It was granted self-governance in 1978, however the Northern Territory is still considered a territory under Commonwealth rule, not a state.