Across the border, but still in Australia (10)
I believe the answer is:
interstate
(Other definitions for interstate that I've seen before include "American motorway" , "American way" , "highway" , "between parts of US" , "road in US" .)
I believe the answer is:
interstate
(Other definitions for interstate that I've seen before include "American motorway" , "American way" , "highway" , "between parts of US" , "road in US" .)