Australian in pit in NE US state (5)
I believe the answer is:
maine
'ne us state' is the definition.
(I've seen this before)
'australian in pit' is the wordplay.
'australian' becomes 'A' (common abbreviation).
'in' is an insertion indicator.
'pit' becomes 'mine' (mining pit).
'a' inserted into 'mine' is 'MAINE'.
'in' is the link.
(Other definitions for maine that I've seen before include "US state, capital Augusta (5)" , "North-easterly US state" , "Part of America" , "American state, capital Augusta" , "N. US Atlantic state" .)