County girl finished first (7)
I believe the answer is:
donegal
'county' is the definition.
(county of Ireland)
'girl finished first' is the wordplay.
'girl' becomes 'gal' ().
'finished' becomes 'done' (both can mean completed).
'first' means one lot of letters go next to another.
'gal' after 'done' is 'DONEGAL'.
(Other definitions for donegal that I've seen before include "Lean dog (anag) - Irish county" , "Irish town" , "County of NW Ireland" , "County of NW?Ireland" , "town and county" .)