Finished with girl from county (7)
I believe the answer is:
donegal
'county' is the definition.
(county of Ireland)
'finished with girl' is the wordplay.
'finished' becomes 'done' (both can mean completed).
'with' means one lot of letters go next to another.
'girl' becomes 'gal'.
'done'+'gal'='DONEGAL'
'from' is the link.
(Other definitions for donegal that I've seen before include "Ireland's northmost county" , "County of NW Ireland" , "Northernmost Irish county" , "part of Ireland" , "Lean dog (anag) - Irish county" .)