Irish county finished with colleen (7)
I believe the answer is:
donegal
'irish county' is the definition.
(I've seen this before)
'finished with colleen' is the wordplay.
'finished' becomes 'done' ('done' can be similar in meaning to 'finished').
'with' means one lot of letters go next to another.
'colleen' becomes 'gal' (I can't justify this - if you can you should give a lot more credence to this answer).
'done'+'gal'='DONEGAL'
Can you help me to learn more?
(Other definitions for donegal that I've seen before include "County of NW Ireland" , "Irish town" , "Lean dog (anag) - Irish county" , "County of NW?Ireland" , "Northernmost Irish county" .)