I mean yeah, the Australian Antarctic Territory (that we basically inherited from the UK, IIRC) is fucking massive. But it's also what we call an "external territory", so I wasn't counting it.

The internal territories are the Northern Territory (practically a state for our purposes here) and the Australian Capital Territory (similar to America's District of Columbia, but with real legislative representation!). Oh, and the Jervis Bay Territory, but for most practical intents and purposes that's another arm of the ACT.