Location Targeting Your Facebook Ads in Australia

Location targeting is to target your Ad to the customers in those right Geo locations. You can target your Facebook Ad to particular locations by State or by Cities or Everywhere in the country (Australia).
Location Targeting - Facebook Ad

You can also include cities within 10, 25 or 50 miles for displaying your ad. When choosing your right locations for your ad, Facebook provides possible estimated audiences as per the locations.

Read more about Targeting Options