Isfahan's country (4)
I believe the answer is:
iran
'isfahan's country' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for iran that I've seen before include "Modern-day Persia" , "Country to east of Iraq" , "Persia some time ago" , "It used to be Persia" , "Middle Eastern country" .)