A golden, unusual county (7)
I believe the answer is:
donegal
'county' is the definition.
(county of Ireland)
'a golden unusual' is the wordplay.
'unusual' indicates anagramming the letters.
'a'+'golden'='agolden'
'agolden' with letters rearranged gives 'DONEGAL'.
(Other definitions for donegal that I've seen before include "Irish town" , "County of NW?Ireland" , "town and county" , "Northernmost Irish county" , "Lean dog (anag) - Irish county" .)