Bishop visiting important part of Ireland (5)
I believe the answer is:
kerry
'part of ireland' is the definition.
(I know that Kerry is a county of Ireland)
'bishop visiting important' is the wordplay.
'bishop' becomes 'rr' (abbreviation for Right Reverend).
'visiting' is an insertion indicator.
'important' becomes 'key' (similar in meaning).
'rr' going inside 'key' is 'KERRY'.
(Other definitions for kerry that I've seen before include "Irish county" , "County < girl" , "County of Tralee" , "County of Ireland" .)