Tricked girl in Ulster town (7)
I believe the answer is:
donegal
'ulster town' is the definition.
(I've seen this in another clue)
'tricked girl' is the wordplay.
'tricked' becomes 'done' (I've seen this before).
'girl' becomes 'gal'.
'done'+'gal'='DONEGAL'
'in' acts as a link.
(Other definitions for donegal that I've seen before include "Northernmost Irish county" , "Irish town" , "County of NW?Ireland" , "Lean dog (anag) - Irish county" , "part of Ireland" .)