Friend from Northumberland hill country (5)
I believe the answer is:
nepal
'hill country' is the definition.
(country with many hills)
'friend from northumberland' is the wordplay.
I cannot quite see how this works, but
'friend' could be 'pal' (pal is a kind of friend) and 'pal' is found within the answer.
'from' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
(Other definitions for nepal that I've seen before include "Country in the Himalayas, capital Katmandu" , "neighbour of Tibet" , "Country located mainly in the Himalayas" , "Asian republic" , "Asian kingdom" .)